Hello, readers!
Garen is a tanky, high damage AD Caster who fits toplane's requirements perfectly, he has high base statistics, good scalings and amazing sustainability, and his main reason of existance is his capability to make his way through crowds of enemies in order to kill the most dangerous ones the enemy team has; his kit is well suited for this role, but it does need the help of some specific items, that we'll cover in this guide for sure!
Apart from his ADC/APC Reaper role, Garen suits well the role of a regular tank aswell, thanks to his Courage and his amazing passive ability: Perseverance, although he lacks an engage, which can make him less useful than other tanks: be aware of this when picking champions, a team without engages is often a team that gets poked down too easily before teamfights start!
Garen is often Built full AD with only one or two defensive items, although this build does work, it's much less gold-efficient, and can turn into a waste of time if you don't get fed enough to realize it, plus remember a tanky champion is always more useful than a full AD one to the team in most cases!
With all this being said, let's get into the core details of this guy!
What is Garen's position in Season 6?



Allright guys. It's november 2015 and the 2016 season (6) is about to begin! As most of you know, there have been huge changes to lots of departments in the game, and as the writer of this guide, I plan on updating every single bit of it to help you guys deal with the changes.
I will focus on Masteries, Runes, Items and Matchups in the same order as I wrote here :)
I can't foresee the future though, so I can't guess with 100% precision what Garen's position will be, but I can give you guys a good anticipation.
My money's on a Garen that works like an assassin (focuses on killing a carry) while having just as much tankiness as he needs to get to the carry, kill it and come out alive. This means we may just take some more risks and build a bit more offensively, taking advantage of the new mastery system, we'll do all we can to keep Garen's role as a tanky bruiser capable of going in, getting a kill and still being able to be frontline :).
This will be harder, won't lie to you. This season my friends, is the season in which you'll have to prove you're a good Garen player, because adcs will be extremely powerful against you and only the best Garens out there will manage to shut them down and carry their teams to victory!
With all this being said, come back soon to get all the info you need about Garen and season 6, I'm here and I WILL provide updates soon :)


What is this "new Garen"?



In patch 5.16 Garen received a huge amount of gameplay changes. In this small chapter I pasted the changelog available at surrenderat20.net for you to read easily here, I will underline all the most important changes when I get the time necessary. All items, combos and gameplay changes will be available in the proper chapters.

Base Stats:
(Nerf) Health/lvl 96 >>> 84.25
(Buff) AD/lvl 3.5 >>> 4.5
(Buff) Armor/lvl 2.7 >>> 3.0
(Buff) Attack Range 125 >>> 175

Passive - Perseverance - unchanged

Q - Decisive Strike:
(Nerf) Silence Duration 1.5/1.75/2/2.25/2.5 >>> 1.5 all ranks
Movement Speed Duration 1.5/2.25/3/3.75/4.5 >>> 2/2.5/3/3.5/4

W - Courage:
(Removed) 20% increased bonus Armor and Magic Resist
(Added) Killing units permanently grants 0.25 Armor and Magic Resist, up to a maximum of 30 total Armor and Magic Resist
(Removed) Active Tenacity component

E - Judgment:
(Nerf) Base Damage per tick 10.0/22.5/35.0/47.5/60 >>> 20.0/25.0/30.0/35.0/40.0
(Buff) Total Attack Damage Ratio per tick 0.35/0.40/0.45/0.50/0.55 >>> 0.46/0.47/0.48/0.49/0.50
(Nerf) Base ticks per cast 6 >>> 5
(Buff) Cooldown 13/12/11/10/9 >>> 9 at all ranks
(Added) Judgment’s spin speed permanently increases at levels 1/4/7/10/13/16, resulting in a total of 5/6/7/8/9/10 maximum ticks of damage per cast
(Added) Cancelling Judgment early returns cooldown of Judgment equal to the remaining duration of the buff
(Removed) Garen no longer moves 20% slower while moving through minions
(Added) Judgment deals 25% reduced damage when striking multiple enemies
(Removed) Judgment no longer deals 75% damage to minions

R - Demacian Justice:
(Added) Passive: The enemy champion with the most recent kills is the Villain. Judgment ticks and basic attacks on the Villain deal an additional 1% of its max Health as true damage
(Added) Demacian Justice now deals true damage to the Villain instead of magic damage.

Pros


+ Great sustain paired with increasing tankiness!
+ Good base damage even after the update!
+ One of the best lategame carry-deleter thanks to his kit and the new "Villain" mechanic!
+ Overall good mobility and cc resistance
+ Good anti-tank thanks to the true damage he received from the update!
+ Only limited by his cooldowns!
+ Good team utility Garen's base statistics are very very good and will give you a great edge in Early-Mid Game against most toplaners and junglers, that in conjunction with your passive ability's unique sustain will make you a real bully in your lane, a strong individual who beats people, while being hard to takedown and almost impossible to force out of lane! But that's not it! Garen's damage and tankiness allow him to turn into a very big pain for enemy carries, only limited by cooldowns thanks to him being manaless!



Cons


- Easy to kite
- His kit lacks crowd control (Silence is good but not enough!)
- Kill potential is not the same on all targets due to the new "Villain" mechanic
- Overall low mobility: speed boost is nice but the lack of a blink or jump forces us to use flash
- Manaless means many items are not gold efficient on him, which is sad Unfortunately, Garen isn't as OP as people who can't deal with him claim, he definetly is good, but he has his flaws, no gap closing (easy to kite), no hard cc (people will always have a chance to run from him), he is unfortunately forced to choose between a limited amount of items due to gold efficiency. Many of these flaws can be fixed during the game, but it requires you to play well and use him to his full potential: follow this guide, and you'll do it for sure, I promise! ;).

1x Greater Quintessence of Attack Damage : Works well with Garen: you already have a good base attack damage and boosting it will allow you to farm easier and, thanks to your abilities' good scalings, it will make your early game trades much more devastating!
2x Greater Quintessence of Movement Speed : They nerfed Garen's base movement speed and his Decisive Strike's bonus movement speed, plus they removed boots' enchantments, the percentage movespeed from these quints is now golden, and I find myself loving the extra mobility, as it makes it extremely hard to just run away from Justice, if you know what I mean... ;)
9x Greater Mark of Attack Damage: Another boost to your attack damage, it will stack up with your quints and Garen's base stats, allowing for easier last-hitting. I used to take 9 of these in Season 4 and Pre-Season 5, but with Season 5 favouring tanks both top and in the jungle I'd recommend you grab only 3 for reasons explained right below. 3 of these along with quints will be perfectly enough for easy last-hitting, as they provide about 10 AD (equivalent of a Long Sword).
9x Greater Glyph of Scaling Magic Resist : AP champions usually don't have that much AP early game, so you don't need to have a huge amount of magic resist so early in the game, while much more will be necessary as the game progresses, since we're trying to be as tanky as we can while still dealing a lot of damage, we'll need this boost as it will help us, along with defensive masteries, in tanking pokes easier, and more consistently.
9x Greater Seal of Armor : Same thing as the glyphs, except this time we take seals of armor and not scaling armor, why? Simple: toplane is mostly populated by AD champions, and even if you're against an AP, their early game autoattacks (especially if ranged) can be a problem to you, having more armor early to stack up with your boost granted by Courage as the game progresses is going to silently help you. Sure, scaling armor may have been nice to be tankier in lategame, but I think that APCs have a much more pronounced tendency to burst people, so I leave the scaling to the glyphs only.

Other possibilites worth considering



As a good summoner, you may have different ways to adapt your playstile to specific champions, and I feel the need to respect that as the guide writer, so here are other alternatives that you can consider with Garen!

9X Greater Seal of Scaling Armor: You scale with passive stats, with your Courage passive bonus, if you get these seals you'll turn incredibly tanky by lategame even if you focus on damage first. There is a MAJOR downside to these runes and that is that in the early game you'll definetly take a lot more damage than you normally would if you are used to the non-scaling seals. Keep this in mind and these runes will be your favourite above the flat ones :)
9X Greater Mark of Armor Penetration: This one is actually a very good alternative, since armor penetration can change the way your damage is dealt and make you much more dangerous during the early laning phase, plus its benefits should remain evident enough (if you pick 9 of these) even during the transition between early game and midgame, there is only one problem: last-hitting becomes harder, especially if you didn't bring 3 quints of AD. If you can get a feel for last-hitting even with these, then it's fine to take all 9 of them.
2x Greater Quintessence of Armor : They can take the place of the seals if you needed them to give you a different stat, scaling health for example. You could stack up seals and quintessences but I'd honestly recommend against using two colors for the same stat unless it's the 15 AD page that I have stopped using a long time ago and has been removed from the guide accordingly :) Pair these with 9x greaters seal of scaling health to keep the early tankiness. Only grab 2 though. A good Garen runes page MUST have at least 1x quintessence of movement speed.
9X Greater Seal of Scaling Health: Nice against champions with flat true damage like Irelia or Darius. You can pair these with 2 quintessences of armor/magic resist (based on lane) and scale into lategame at ease against high flat true damage compositions without compromising early tankiness.

So in general, you can pick scaling runes over flat runes, or viceversa depending on how much you care about early game or late game. I generally prefer using runes to give Garen a boost to his early game, and give more power to his scalings, remember his abilities scale from his AD, and due to Courage not boosting bonus armor and magic resist anymore, he needs more help early in order to be as much of a bully as possible!

PATCH 5.22 AND NEW MASTERIES: Yep, masteries have changed alot. I'm working constantly on keeping the guide as uptaded as possible and I'm trying really hard to find the best setups for you guys. Alternative setups may show up here in the future, but when you come here to read the guide, keep in mind the best one I can recommend at the time you're reading is the one at the beginning of the guide. Check back every now and then to see if I changed something! :)



Garen is tanky. Insanely tanky. And what you must do when playing with him is have tanky masteries, no matter how you'll build him, the added tankiness these masteries will give you is going to help you greatly.
For Offensive Masteries we take damage increases on our spells and a degree of sustain through lifesteal and spellvamp that will help while trading, you can prefer to get extra AD instead of those 2 stats, but I generally prefer them over the rest to have better trade outcomes. Rest of offensive masteries is just a regular boost to your damage over the course of the game, nothing special there.
The defensive masteries consist of a boost to our general defenses (armor + magic resist), extra health for better tankiness in lategame, tenacity and some sustain/damage through our Keystone mastery and the neat cdr on summoner spells that helps you have extra mobility faster (flash), more damage if you use Ignite, and more pressure if you use Teleport :).
Q: Sure that 12/0/18 is the right way to go? Would 18/0/12 work aswell?
// Garen's potential of becoming a Bruiser is extremely high, and I don't think it'd be a bad idea to use a more offensive mastery setup. The issue I got is with the keystone masteries in the Ferocity tree... They simply don't seem to be worth the points you spend in that tree to get to them. So instead of focusing on extra damage in the masteries, I'd rather focus on that in Items and builds, where we can really make the difference, instead, I prefer defensive masteries to boost our tankiness and allow us to win lane easier than we would with an offensive setup.
That all being said, you can totally change masteries if you prefer a different setup, my opinion isn't important enough to delete yours :).

Flash
// Teleport in the direction of your cursor
Flash is the best summoner spell on Garen (in my opinion) because it gives him the instant teleport ability (a.k.a. engage) that he lacks, and can also be used to escape quickly and over walls if necessary.

Ignite
// Lights up an enemy on fire, dealing a certain amount of true damage for 5 seconds
Ignite is an amazing spell for Garen: it's an useful way to finish off enemies that are escaping from you pre-level 6, and it will couple very well with your Demacian Justice after you hit level 6. Nothing prvents you from using Ignite on an enemy and then Demacian Justice on another enemy, to get a double kill, just make sure you are a good calculator and you'll do this often! ;) Don't forget that you can also use it on high lifesteal/healing targets, to half their regeneration.

Other viable summoner spells



Teleport
Teleport will allow you to teleport to a tower/ward/friendly minion
Teleport is a very common summoner spell for toplaners and Garen isn't an exception, the ability to back, shop and then pop out of your turret/minion is really nice. Not to mention the fact that it's amazing to just come out of a ward in a teamfight, turning the odds to your favor: a tank that appears all of a sudden can change things, especially if he's Garen! Why don't I pick it then? Simple, Ignite will allow you to snowball if used properly: it's just too good on Garen. In general, I'd say you should pick Teleport instead of Ignite against ranged enemies that will force you to recall often, or in case you are the only tank in your team and all of your teammates are squishy and need your presence often mid-lategame
Also, teleport beats ignite if you are in a 5 man Ranked with people you can communicate with. That makes every teleport count unless you guys are terrible at cooperating, into which case I'd recommend you get better premade friends to play with if you want to win and climb elo ^_^

Ghost
Ghost will boost your movement speed for a limited amount of time and will make you ignore unit collisions
Ghost can be seen by a Garen player in 2 ways...
[1] A boost that will stack up with your Decisive Strike and an unit collision ignoring spell that will stack up with your Judgment, an all in all good chasing spell that has a lower CD than Flash and can be used to escape aswell;
[2] Something that will add up with your champion abilities but won't fix one of the cons Garen has: your engage. You already have a movement speed boost thanks to Decisive Strike after all, so another "walking" spell won't change your game much.
It's as usual a preference matter, though to me the instant teleport Flash can give you will make a bigger difference most of the time.

Exhaust
// Will reduce enemy movement speed, attack speed and damage output for a limited amount of time
Troll lanes exist, hard lanes exist and this spell can help you when trying to stick someone that always runs away to the ground ( Vayne, Teemo, etc...), so you can deal more damage and increase your kill potential. It works in very specific cases though, and sacrificing Flash for this may leave you with less possibilities in different situations, while sacrificing Ignite/Teleport for this also isn't lovely. You can use this spell if you want, but I generally don't recommend you do.

Doran's Shield
Because Garen won't receive bonus armor and magic resist from Courage anymore, this item just turned a little more useful. Because of gold efficiency and Garen's still pretty goos natural tankiness I would continue to recommend other starts. Besides, this item stays one of the best for beginners, as it does provide good early lane stats.

Cloth Armor
Because Garen won't receive bonus aror from his Courage, starting with this item isn't as effective as it was beore, but the truth is that it is still a ver reliable start against AD casters and basic attackers. Not only will it give you more armor to stack up with the flat amount you now earn from farming with Courage it also allows for amazing sustain in lane thanks to the 4 health Potions.

Long Sword
This start is mostly useful when your lane opponent tends to be tankier than you early game and makes you risk death due to him outtrading you (people like Shen or Malphite are in this category). It also helps you in last hitting which has a huge value. I normally prefer defensive starts but this start should not let you down regardless.

Boots of Speed
This is the main start you will want when you are fighting against a ranged enemy or a mage. You are melee and you need the speed boost to make sure your Decisive Strike lands, allowing a full burst to happen. They also to towards Mercury's Treads which are often the first item you will finish against a ranged/heavy cc enemy! Plus 4 pots are a great tool in lane, and this start allows you to get them!

Ruby Crystal
Healthy start which just turned more effective after the gameplay update. Due to Courage not boosting flat resistances anymore, getting early health to boost your resistance and passive is a great plan. Mostly effective against melee ap enemies ( Ekko or Akali and similars), the item goes towards The Black Cleaver, meaning you can start with it when you know you will have a big advantage in lane too.


Items for the rest of Laning Phase and the Mid Game



Chain Vest
This will be your go-to item for AD lanes, it only gives you armor, and it builds into most of the defensive items you may need for the midgame and the lategame. Not much to write here, the item is good and you can pretty much build it every time you are facing an AD based toplaner.

Warden's Mail
This item is similar to the Chain Vest but transitions into Randuin's Omen only and provides a basic attack slowing passive, meaning you should build it against enemies that are:
1) Basic attack/attack speed based, because we want the passive to be a factor, the 5 extra armor point aren't worth the extra coin if the enemy is an AD caster
2) Crit focused, because when we get Randuin's Omen that's what we'll try to counter
So in general you can focus on this item if you're facing enemies like Yasuo or Tryndamere to reduce their damage output by quite a bit.

Spectre's Cowl
Essential item against AP focused toplaners which provides great tanky stats and counters the poke/harrass tendency that APCs have with their abilities. You should build this item in every balanced game as it will turn into Spirit Visage, giving it priority if you're against an AP based enemy like Teemo or Vladimir.


Phage
This item is a good early game mixed one. Gives you a good amount of AD and a good amount of health to go with, plus a passive that further boosts your engage by activating after you land a Decisive Strike or a basic attack. Sometimes you can even basic attack, then proceeding with Decisive Strike for extra movement speed! This is the main damage source you will want because it turns into the Black Cleaver.

Executioner's Calling
Damage and Grevious Wounds to counter your enemy laner's sustain. Not too gold efficient and can be useless if you know how to manage your Ignite properly. Should you have Teleport and be against a heavy sustain enemy like Vladimir or Volibear, then this item is a blessing that you'll only be able to afford if you manage to get the coin to buy this AND a defensive item. As you may expect it's not that easy, but if you farm properly it won't be an issue for sure. I just don't think this item is a good "every game" item for Garen.

Serrated Dirk
AD + armorpen, that's the brutalizer (weaker) for you. This item goes towards Maw of Malmortius or Youmuu's Ghostblade. It's a very good item if you get ahead a Low difficulty matchup, or when you get extremely far ahead of your enemies.

Hexdrinker
An item that basically merges damage with resistance and is very helpful against AP enemies top. Picking this item against low CC APs top is basically buying a ticked to win the lane (an example is Vladimir). It's a big amount of AD, a great amount of MR and a great passive (a shield) that will allow you to trade when you would normally have to back off (this often catches enemies off guard, and allows you to get free kills you'd normally not get). It's not ALWAYS the best damage item to pick against APCs but it's helpful in most lanes. MORE ON THIS IN MATCHUPS SECTION. THANKS TO USER "SREEN" FOR RECOMMENDING THIS ITEM!

Kindlegem
Health + CDR. 2 stats Garen benefits from greatly, and because this item turns into both The Black Cleaver (our offensive item) and Spirit Visage (another defensive item), this item is a true jewel. You can purchase it once you have some flat resistances (Armor and Magic Resistange) and an offensive item like those listed above in your inventory. Picking the item you want to turn your Kindlegem into is highly situational. More on this below and in the Matchups section.

Giant's Belt
An item that provides lots of health, and turns into many defensive items over the course of the game, like Dead Man's Plate or Warmog's Armor. We normally prioritize flat resistances like Armor and Magic Resistance for the early game, but once those are set up, and you got a Phage or an Hexdrinker (depends on the enemy you're facing) in your inventory, you can build some extra health, taking this in case of an AD lane.

Bami's Cinder
Health and an AoE magic damage passive. This item turns into Sunfire Cape and deals a fair amount of magic damage per second to all the enemies close to you. This means that if you buy it too early, you may end up pushing your lane alot, denying yourself farm and exposing to ganks. However, there are lanes in which this item is pure gold. For example, say you're fighting a Darius or a Renekton who's built a Chain Vest and clearly wants to go towards Dead Man's Plate or sunfire, this build will protect him from alot of your physical damage, by building Bami's Cinder you complement your kit with some extra magic damage which can help you greatly in trades. Or you're facing a very good Riven who always tanks your damage using her shield, by building this item you'll damage her whenever she tries to trade with you and counter her shield, because it only lasts a few seconds.
So in general, you want to build this item against an AD focused enemy who's building tanky to counter you.

Jaurim's fist
Good laning phase item that makes you go through the mid-game relatively well too. It provides health that scales up with every unit kill (exactly the same thing as your W's passive component) at a rate of 5 health points per unit killed. Is this an "every game" item? No. It gives 150 health off the bat (not that much) and only gets gold efficient provided you're managing to farm alot, and this just doesn't always apply, especially if you're not having an easy time in lane. The 25 AD is indeed 10 more than the Phage gives you but you must keep in mind the Phage also provides mobility and goes toward an item you need to rush as fast as possible once you got your defenses setup, buying Jaurim's Fist can delay The Black Cleaver and that isn't something you can always do lightly.
With that being said, you should build this item against low true damage based enemies (like Irelia or Olaf (enemies that deal true damage but in a very small amount).


Executioner's Calling
Damage and Grevious Wounds to counter your enemy laner's sustain. Not too gold efficient and can be useless if you know how to manage your Ignite properly. Should you have Teleport and be against a heavy sustain enemy like Vladimir or Volibear, then this item is a blessing that you'll only be able to afford if you manage to get the coin to buy this AND a defensive item. As you may expect it's not that easy, but if you farm properly it won't be an issue for sure. I just don't think this item is a good "every game" item for Garen.

Guide Top
Core Items

CORE ITEMS FOR ALMOST EVERY SINGLE GAME



The Black Cleaver
CORE
Best and only really mandatory damage item you will ever want on Garen. It gives AD, health, cooldown reduction which are all gold perks for the G-man. Besides, the two passives are amazing aswell, the armor shred is a huge deal for enemies as they will be weaker to you and to all your physical damage based teammates. The "rage" passive is also perfect in your kit, as it will allow you to stick to enemies you engage much more easily, providing extra mobility! This item is pure gold on Garen and it's always safe. You can build it in any game in any condition.

Youmuu's Ghostblade
Damage, cdr, armorpen, mobility. Pretty awesome right?
Sure we don't get any tankiness and that's why I don't think youmuu's is as important as a Black Cleaver, but it's definetly up there with it. If the enemy team doesn't stack up armor, or you are going for the flat armorpen build, get this item as your first main damage item. It's obviously not that great of a choice if the enemy team is too far ahead, due to no tankiness, in that case it's best to get the Black Cleaver, but if you're ahead, go on and get this item no problem.


Boots



Ninja tabi
More amor and auto-attack damage reduction is nice, and they cost less than Mercury's Treads, so in case you are fighting an AD enemy and you don't wanna wait for your next back to have boots, you can buy these. Maybe swap them for Mercury's Treads mid-lategame, because you need Tenacity for teamfights much more than you'll need auto-attack damage reduction. However this isn't true if the enemy team has 2 or more autoattack based champions like Tryndamere or Yasuo or Olaf

Mercury's Treads
Yes, they cost more than Ninja Tabi and won't block auto-attack damage, but their passive will boost your resistance to hard CCs even higher than it is by default, making you almost unstoppable: when you decide someoene dies, SOMEONE WILL DIE. In addition, you also get some more MR, which is always nice ^_^. This is why I tend to prefer these over Ninja Tabi often, especially because Tenacity is just broken on Garen

Boots of Swiftness
These boots are golden on Garen when you're facing a ranged opponent, no matter if he's AD based or AP based ( Vayne, Jayce, Teemo, etc...). They'll make you faster than your enemy, allowing you to close the gap faster and hit them more often, leaving them with less chances of escaping, sometimes this makes up for the lack of defenses these boots suffer from. Regardless, after patch 5.17, with the base speed reduction and the Q's speed buff nerf, these boots turn more viable for lanes that favour you. ATTENTION, though! If your enemies have lots of CCs, Mercury's Treads beat these boots, Tenacity is better than raw speed in this case!


Core ARMOR Items



Dead Man's Plate
Brilliant item for Garen. Armor (a good amount too), Health, passive movement speed, a potential slow (huge addition on Garen's kit) and extra damage on a basic attack. If you have 100 stacks and activate Decisive Strike you will move as fast as a car and hit like a truck for a huge amount of damage, which is brilliant both in laning phase and in mid-late game. The item is also relatively cheap, this is also a great reason to build it first often, a cheap item with good stats and brilliant passives that make Garen get stronger in all his aspects fits the definition of first item in my opinion. Just read this full section as sometimes you may prefer other first items.

Sunfire Cape
This item is very good on Garen, it will add armor, health and a magic damage passive, which is very useful on a champion entirely based on AD like Garen, as it will surprise opponents who'll build armor to avoid damage from you. As many say, and they're right, it's a core item for you and you should be building this in most of your games, but there are also games in which you may prefer other solutions, depending on the role you want to fill in your team.

Randuin's Omen
An item similar to Sunfire Cape in its base stats but different in its target, to help you choose between this and Sunfire there is a small paragraph below. This item has recently been nerfed and changed in some ways. The nerf on armor is not too big of a hit, as 60 is still a good amount to go with, but the nerf on health is a bigger deal, with it, Randuin's now gives less health than a full Sunfire Cape. The new passive that reduces critical strike damage stacks up whell with the masteries I choose, plus the AoE slow is now stuck flat at 4 seconds which is very good for Garen. You should build this item agains heavy basic-attack/critical strike enemies like Tryndamere, Vayne, Jax etc...
Sunfire Cape vs Randuin's Omen vs Dead Man's Plate.

Every matchup has its own solution and these 3 items are all brilliant choices regardless.
The new item called Dead Man's Plate, is a huge deal. It is one of the best first items Garen can ask for: armor, health, extra movement speed with the passive and also a free damage boost every now and then. That is why you can build this item in every AD matchup and feel safe with it.
You can prefer Sunfire Cape against AD casters and enemies who don't rely on attack speed like Riven or Renekton, as the armor is enough and the damage boost the passive provides is considerable, especially because it's magic damage. Also you can prefer Sunfire against enemies who build armor against you, to boost your trading potential.
You can prefer Randuin's Omen against high basic attack and critical strike based enemies like Tryndamere or Yasuo, but it can work against all other AD based enemies too.
Keep in mind the three items are similar and swappable: building one instead of the other will have a bigger difference based on the enemy team's composition!

Thornmail (Highly situational)
Thornmail is a very very good item when built against the right enemies, this is why although you won't build it every game, I consider it to be a core item in the build. It gives you 100 more armor and a passive ability that will give back 15% of the damage you receive from BASIC ATTACKS + 25% of your bonus Armor (including the armor you get from Courage stacks) to the attacker as magic damage. This item is the best anti-ADC item that exists, and it works well against auto-attack based melee champions too. The reason why I didn't include it into the main build is that it only boosts your armor and doesn't give you other base stats as other items do, plus its passive is highly situational, so in a normal game I almost never build it. You can swap this item with Sunfire Cape or Randuin's Omen or Dead Man's Plate when the enemy team has 1 or more extra auto-attacker apart from the ADC, or when the enemy ADC is really fed and you want to stop him.

Core MAGIC RESISTANCE Items



Spirit Visage
A recently buffed great item for Garen in all of its stats: more health is good, more health regen is good, CDR is PERFECT, MR is PERFECT, and its passive ability will boost your Perseverance by 20%. It's probably the best Magic Resist item for Garen because all of its stats work amazingly well with Garen's kit.

Maw of Malmortius
This item isn't as CORE as it may seem, but if you have an Hexdrinker in your inventory, you will want to turn it into this item without question. AD, extra magic resistange for lategame and a shield that scales based on your already high MR? What else do you want? Armor Penetration? Oh wait... You get that too! You should build this item when you have built an Hexdrinker in midgame, however, the time in which you should actually complete the purchase depends on the matchup and also on the enemy team's composition. Say you're against Akali top and you're winning: building this item makes her completely useless, and this obviously can apply to a Vladimir you just may have conveniently rekt earlier in the laning phase. In general, 10 armorpen is a good asset for going through laning phase and the early mid-game, but will fall off in the lategame, meaning you can't replace The Black Cleaver with this item, and most importantly that if the enemy team is particularly tanky, you will keep the Hexdrinker until the very lategame before getting the full Maw.


Core HEALTH/MIXED items


Mixed items are items that provide both health and damage to a degree.

Sterak's Gage
Another great item for Garen. Increases your base AD (which has been buffed, as it will increase a little more every level), gives you health, and the passive which turns you big, increase your AD even further and also gives you a shield that scales off your max health is a huge deal. This item should take Warmog's place in the full build. You can build this item instead of Youmuu's (while getting Warmog's too) when enemies are relatively squishy and have 2 or less bruisers, as you will not need more armor penetration nor mobility from Youmuu's Ghostblade while taking great benefit from extra AD and Health.

Titanic Hydra
A beastly item for all fighters and melee attackers, I did build it a few times on Garen and it does increase his damage output by quite a lot. The problem is that it's yet another Health based item that doesn't really give too much defense, especially if you already have over 3500 health, the difference isn't too big. So I'd say you can build this item when you are ahead by alot, just after The Black Cleaver for extra damage and offensive power, or as your 6th item if you feel like the enemy team doesn't have alot of damage and you can be tanky enough without having to fill your 6th slot with a fully defensive item. You can use its active right before a Decisive Strike for a huge amount of damage, as it will stack up with Dead Man's Plate's momentum stacks and your ability's already good base damage!

Warmog's Armor
Changes to Warmog's are relatively negligible on Garen, thanks to his passive. Besides the new Sterak's Gage is a very good replacement for this item in lategame. This does not mean that this item is uneffective. You should build this item if you had to purchase a Thornmail, if the enemy team has Darius/ Cho'Gath/ Shyvana, or when you are up against a squishy team with high mixed damage output.
Also, if you purchase a Youmuu's Ghostblade and end up with low max health, do consider this item.

Titanic Hydra VS Sterak's Gage VS Warmog's Armor


These 3 items are damn good on Garen, all 3 of them. Sadly, in most games you'll only build one, in some, 2 at max, but unless you are trying out the NEW Healthy Garen Troll Build, you won't build all 3 of them.
So how to choose? Of all these 3 items, the most flexible one and the one that suits Garen's role better is Sterak's Gage. Why? Simple. Health, Extra Base AD and the amazing passive that doubles the good base AD boost (around 30 at level 16, turning into around 60 with the passive proc), providing an offense-defense mix that is very useful.
When should you grab Titanic Hydra?
The new Hydra's damn good on Garen and on any fighter. The AD boost is neat and the passive and active are a huge deal when you're carrying, because they allow you to 100% - 40% a carry with just your Decisive Strike, especially if you also have completed your Dead Man's Plate, so its spot is obviously in a situation in which you are ahead by a lot. You already got 30 extra Armor and Magic Resistance from Courage and you completed The Black Cleaver along with some Armor and MR from unfinished items? Buy Hydra and you will become a real Juggernout, high tankiness with flat stats, high health and huge damage output for your team to be carried with!
When should I get Warmog's Armor?
Warmog's comes in handy when the enemy team's damage output is ridicolously high AND mixed especially if you are behind, because they will get armor/magic penetration, making your flat resistances less of an aid in fights. Also, you can prefer this item in games filled with NOT max health based true damage, as it will give you much more time to live with. You can opt for a Warmog's when the enemy team is filled with pokers like Jayce, Xerath, Nidalee, etc..., so you can basically sponge all their pokes and then sustain them all back to full health in no time! Finally, you can build Warmog's when the enemies are full AD instead of Spirit Visage, so you don't loose the boost to your passive that item gives you.

The Trinity Force




Controversial item on Garen. Most people don't build it and I don't build it either normally. But guys, it's tons of damage for the reasons stated below:
AD;
Movement Speed (and this is huge);
10% CDR that brings us to 40% with the normal build;
20% critical strike chance, making TriForce a good replacement for Youmuu's in the lategame;
Passive ability makes Decisive Strike deal approximately 600 physical damage in the lategame.
However, I feel the need to specify why the item isn't CORE in my opinion:
Mana goes to waste (less gold efficiency);
Attack speed feels useless;
Rage passive completely outscaled and outshined by The Black Cleaver's passive which is much better, rendering TriForce's version useless if you already got cleaver (which you will do, because BC is CORE);
Is this item an "every game" item? Nope! The cons are factors and you wanna consider them before you spend your money on the TriForce...
To answer the obvious question you are having for me right now, being "When should I get this thing then?": I'd say you can build this as your 6th item if your enemies' damage output is low in a normal game (a game in which no one has a special advantage of some sort).
Also, if you're winning by alot, you're going extremely well on damage and you're carrying, getting TriForce can make your damage skyrocket, although you will transition into a relatively squishy midgame, making plays harder to make.