This is actually a progression that I made from both the recommended items that Riot suggests, a few ideas coming from knowing/playing Garen, and a few guides from both here (Mobafire) and LeagueCraft. With this build you will be causing so much damage to the enemy while absorbing your fair share of it at the same time.

There might be some questions as to why this build is called a carry build and not just another off-tank build, so I'll address that now. Yes, if you follow this guide you will be able to stand in the fight. However, the damage that you do allows you to get a staggering amount of kills in a single game.

The few times that I have managed to complete the entire build (does not happen often, as this Garen can do tons of damage) I've ended up selling off the Sunfire Aegis (remember that this is late-game where people have 2k+ health) to get the Last Whisper to give Garen that extra damage ability.

With this guide, I will first highlight the reasons I pick certain things and then in the next section I will make a short summary of what I mentioned (hereto refered to as the TL;DR versions). This will be used on all the sections save the Summoner Spells due to the nature of that section. I liked this style the first time I used it and allows a quick glance at things without having to read too deeply into them for those people that need a guide during a game.

V 1.000.000 Initial Release (4/6/2011)
V 1.000.001 Small Update to Grammar and Spelling (4/6/2011)
V 1.001.000 Added in Other Items and Other Items TL;DR sections (5/12/2011)

None ATM

A simple rune choice that should look familiar if you have seen my Jarvan IV build on here.

For the Mark section of your rune page, I suggest getting nine Greater Mark of Desolations. I do this because all of your attacks (save for Demacian Justice) are physical based and will benefit from being able to pierce more of your opponents armor. Seems to have a greater affect early game where nobody has much armor.

Next up is the Seal section. For these I recommend nine Greater Seal of Vitalitys for the extra health. While this will only account for 3.5 damage at level 18, it does give you a greater life level which works well with Perseverance. That nine health really is a big deal at level 1, just trust me here. I've lived through ignites with between 1-9 health left thanks to these runes!

For the last of the main runes, there are the Glyphs. Once again nine Greater Glyph of Cooldown Reductiones (confusing for me to type out like that) will make a big splash. Because Garen is one of only three champions who don't use mana or health with their abilities (the others being Katarina and Renekton) having that cooldown reduction will allow his abilities to come back up quicker then normal. Very handy early game where you will rely greatly on Judgment for your damage.

Lastly, we have our Quintessences. I personally pick Greater Quintessence of Movement Speed quints because there is usually not much scarier then a spinning Garen flying towards your face. Add in speed bonuses from the boots, Ghost, the Force of Nature, and Decisive Strike and you can really go fast.

Unlike my Jarvan guide, I will actually say that the Quintessences are up for debate. The other ones that would work are Greater Quintessence of Desolation, Greater Quintessence of Scaling Attack Damage/ Greater Quintessence of Attack Damage, Greater Quintessence of Revival, or Greater Quintessence of Defense. Quite a bit of variety that is up to the user. You could easily find that a Quintessence not mentioned works better for you, so once again I leave it up to you to make the final decision for yourself.

9x Greater Mark of Desolation Greater Mark of Desolation
9x Greater Seal of Vitality Greater Seal of Vitality
9x Greater Glyph of Focus
3x Greater Quintessence of Swiftness

OR

Quintessences of your choice.

I run with a standard 9/21/0 build for the masteries. However, there are some differences between standard for Garen and standard for everybody else (most notable in that he avoids the Archaic Knowledge mastery and gets some ArP), and I will highlight these things.

Starting in the Offense tree, we get they standard crit-chance masteries for the AD champs but we also need to stick a point in Archmage's Savvy to get the next tier. Since Garen is strictly cooldown based and is a mana-less champion, giving him as much CDR as possible helps maximize his DPS. Grabbing that two more ArP is actually a big deal in the early game but tapers off as the overall level in the game goes up.

Now on to the Defense tree where we spend most of our time. Increasing our defenses from both physical and magical attacks in the first tier will help us early game, and even in late game that little bit could make just enough of a difference to save your life. With no other real options for the second tier, being able to avoid enemies attack occasionally (and get sped up by it from a tier three pick) would assist in getting out of a fight when you need to or just keep you alive to kill more minions. Taking everything from tier three gives us that speed boost when we dodge and reduced damage (most prominent from minions).

Yes, the Defense tree warrants enough attention for a second paragraph. Working our way to tier four gives us more health (can't have enough in this game for Garen) so we stop dying as much! Tier five gets skipped and in tier six we pick-up the only mastery available, sharply decreasing all damage taken by 4% (further increased with Courage).

Use the reference up top!

The most recently changed section, there is a good amount of leeway when it comes to items. I will go over the core items you want though, regardless of enemy team composition.

Since Garen is entirely cooldown-based, the Ionian Boots of Lucidity allows more ability spamming to increase DPS as Garen (and acts as one of THE needed items for this build). The boots slot used to be filled with Boots of Swiftness but since the .114 patch Garen is faster by default and thus with my recommended Quints he needs no more speed.

A staple for ALL Garen builds is the Sunfire Aegis, and while they no longer stack it is still a potent item. All melee champions benefit from its effects, but Judgment combined with this gives us a great amount of damage done per second. Add in more health and armor and its just asking to be taken...

Garen has one of the highest lvl 18 health levels, and thanks to the runes/masteries we selected and the Sunfire Aegis he continues to climb the list. With health being such an integral part of these builds (mostly thanks to Perseverance) getting the extra damage from Atma's Impaler just makes sense to me. Again though, more armor helps and with that extra crit chance all of Garen's damage just went up!

Boots of Lucidity
Sunfire Cape
Atma's Impaler

At this point I have covered all the items you should be getting EVERY GAME. From here on out I will cover items that can be picked depending on how the game is going and the enemy team composition.

Force of Natures work wonders for Garen. Extra health regeneration, the .35% health per second (stacks with his passive for .85% per second), and that magic resist makes this one of the BEST items to get when going up against 2+ magic-based champions in a game.

Frozen Mallet, health and attack damage? Oh yeah, did I forget to mention the health gets Garen even MORE attack damage thanks to Atma's? Well it does, and he becomes a beast with it. The slow is nice too, though when you move as fast as my Garen does its usually not the issue.

I know that I'm starting to sound like a broken record at this point, but the health and health regeneration from Warmog's Armor helps, even more so when you already have that Atma's and the FoN. Yeah, this guy gets TOUGH to kill and hurts bad while doing it.

If for some ungodly reason, the game goes after I get all these items I end up selling off the Sunfire Aegis and get a Last Whisper instead (taking no noticeable change in attack damage) so that my attacks are actually getting through the enemy's armor!

Randuin's Omen is helpful if the enemy team has lots any of the major AD/AS champions. Extra health and health regen also add to that ability to stand in the fight for longer. The unique effects work well (especially the CDR) and the ability to slow the attack speed and move speed of all enemy champions around you would help immensely against opponents like Master Yi and Teemo.

Force of Nature
Frozen Mallet
Warmog's armor
Last Whisper
Randuin's Omen

When you want to do massive amounts of damage to the opponents, the best skill to use (against champions at least) is Judgment. If you manage to hit an opponent with every hit at level one, they will be lacking a good portion of their health already. Damage just gets better as it levels (and you get more AD/Crit%). Lets not forget that if you use this skill while a slow is on you, that slow is just gone. All future slows on Garen while this skill is active are reduced by half their duration.

Since we want to minimize the damage we take, picking up Courage early on gives us that extra armor/MR that will keep us alive, not to mention the active effect of reducing ALL non-true damage done to Garen by 20% AT LEVEL ONE. Assuming that an enemy Karthus has no AP (what a bad Karthus that would be...) and he uses his ult, that 20% reduces what your MR has to take down to 200 damage. I shouldn't need to tell you why this is helpful....

Garen has no real hard CC, and his only non-item CC comes from Decisive Strike in the form of a silence. This skill also increases damage done, not just to minions and champions but to anything it manages to hit (great for getting that last hit on the turret hitting you). Ability heavy champions should be the first target for this skill, though if there are non around you should just use it. Did I forget to mention it gives you a slight speed boost as well, letting you escape easier?

Finally is Garen's ultimate, Demacian Justice. My suggestion is to ONLY use it on low health enemies to pick up the kill (try not to KS though) since it does extra damage for every 3.5/3/2.5 health the enemy is missing. Tanks suffer most from this though, since they could actually be at half health and die from a single strike of this fearsome ability.

Levels 4, 10, 13, 15, and 18

Decisive Strike

Levels 2, 8, 12, 14, and 17

Courage

Levels 1, 3, 5, 7, and 9

Judgment

Levels 6, 11, and 16

Demacian Justice

Suggested Spells

Teleport: This used to be Ghost until I realized that I usually have no issues escaping. Instead, this is for getting back to the fight almost instantly. See a tower that needs saving? Just head down there! Team fight going on at mid and minions/shrooms/standards/etc. are close by? Teleport in and save the day!

Ignite: Mainly used on enemies that are trying to escape, but it has its uses when the enemy isn't falling back. Since this does true damage there isn't really any way to stop the damage, making it great for dealing that extra bit of damage to the enemy to execute them with Demacian Justice.

Workable Spells

Exhaust: This would let the enemy be in your melee/ability range more and cause them to be less damaging to you, but with your speed they need a heck of a head-start or a flash-like ability to escape. Has its uses though, such as on Tryndamere while he is Raging.

Flash: Need just that little bit more distance on somebody to kill them, but don't really want to waste your Decisive Strike to get there? Enter flash, and there you are ready to kill them. Sucks if they have it too though...

Cleanse: Enemy team have just too much CC on them? Cleanse makes it all go away! If you are that hurting for CC protection just get Mercury Treads and a Quicksilver Sash. Still, this works well early game against cheap level one two-second stuns (AKA Sion and Taric).

Avoid These Spells

Revive: To be honest, this would not be here if it were not for the nine minute(!) cool-down, and the recent buff to respawn timers early game.

Smite: No. Just no. You do not do enough jungling to warrant this as a spell.

Fortify: This works best on support characters. While shielding a turret is nice, your job is to do damage and scare the enemy away, not let them attack a turret.

Rally: This is wasted on Garen. Healing shouldn't a an issue AT ALL and you will be stacking enough attack damage that it would only be useful (if only barely) during a team fight.

Clarity: Why oh why would you take a mana-restoring ability on somebody that doesn't even use mana? WHY?!?

Heal: Garen has enough built-in heal, not to mention how often I get the Force of Nature.

Ghost: As stated before (and shown above in his stats) this Garen is faster then almost every single other champion in the game. Only two that would rival him would be Teemo with his active Move Quick and Master Yi while in Highlander (though they both use this to run away 90% of the time).

Clairvoyance: If you need line-of-sight so bad get wards, or if somebody on your team has a Wriggle's have them ward it for you.

A speedy Garen that has the potential to do massive damage to the enemy, coupled with tons of health and health regeneration make this build something that all should fear. Not many champions can stand up to this massive health monstrosity and live, even less if you have your team around. Going 8-0-12 is entirely possible, and I HAVE done this before.

Thanks for reading, and I hope you guys will rate this as you see fit (and explain WHY you think it deserves it).

A video version of the guide in the manner of the Champion Spotlight or XboxAhoy's Black Ops weapons guides.

Gameplay Videos!