Hi, i'm Hyugarr from EU, and also french (like freakin Renekthon) so please forgive me my english mistakes. I'm here to share my experiments with gnar because i think he is a very misunderstood champion. I'm currently 15-6 in ranked games with Gnar and played much more games in normal.

I played him many times with a friend in ranked queue against diamonds (i'm only platinum , but he is diamond so we meet diamonds) and i think he is a very consistent champ that can bring alot to his team, even if his early went bad.

I will talk about the best, non trolling way to build him, which is full tank. I'll explain why everything else is not realistic for serious games. Be sure to review and comment my guide if you think it is interesting and deserves improvements.

When you look at Gnar , he has a very poor scaling with offensive stats. If you don't trust me go play 2 games, the first one with a semi tank or hyper carry Gnar and the second one with Tank Gnar . You'll notice a bare difference in damage. Why ?
Because what is hurting on gnar is the W passive Hyper , and this spell screw up your entire perception of the champion .

So you would like to buy attack speed to increase your damage right ? But attack speed is totally useless when you play the mega gnar form which is about all in combo . You have some time to auto attack in between your combo , but you can't do much because you are melee and need to stick to your target . Mega Gnar will be your objective for every teamfight . So attack speed is kinda wasted ...

The good mindset for building gnar is to think about something that will support both of his forms . Tankyness is clearly good for mega form , but he will also supply the baby form because you can't effectively trade in the top lane without resist , you'll just blow up to ANY combo . However after you bought some resist to survive that burst , you'll be able to trade as your ennemies try to disengage after their combo with your range and Hyper .

Offensively , you would like to have ARPEN , because teamfight wise it's the best single offensive stat for mega gnar . Poor scaling with AD , attack speed , but high base damage . Moreover MEGA gnar has the best base attack damage in the game , so one damage item is really giving him alot : trinity force . Trinity force gives a bit of everything , so is basically useful for both form and give you the best passive for MEGA GNAR : 200% of your base ad to slam inbetween your combo , that's alot of damage on squishies trust me.

To sum this up : what you want on gnar is tanky stats and ARPEN + trinity force passive because they are useful in every form , but far better in mega gnar form which will be your main teamfight form , so you want to focus on it , without getting behind in lane .

ARPEN because it's the best offensive stat (you can swap for AD if you want easier last hitting)

Armor and Magic resist will help you with your early weakness to wombo combos. I don't want to take health because mega gnar has a lot of health , so i think it scales better to take armor and mr but it's up to you.

21/9

Even if you build full tank , your role in tf is to disrupt and do massive damages to squishies , which is easier with that AD and ARPEN in the offensive tree

9/21 could world if you play like a dedicated tank to become beefier

Get warding trinket then take an item with pots depending on your oppenent :

Doran's blade for ranged harass against low pressure or even match up

Doran's shield to counter auto attackers

Armor to counter physical spell champions

Boots if you really need the movespeed to dodge skillshots , or going against AP with good poke (you'll get 4 pots)

You want to grab 1 doran's blade (or even 2) for lane dominance/sustain

you need to buy one armor or one mr item (sunfire/spirit) depending on your oppenent . It will allow you to survive his burst , and so you will be able to outtrade him , because of your high base damage . You may want to take an early brutalizer if you start snowballing , just after your chain mail or negatron clock . It will give you a big edge over your oppenent . You can turn it into a black cleaver later if you have an AD team for the aoe armor shred .

After this you can work on trinity if ahead, but do not plan to join teamfights if you don't have at least an armor chain or negatron cloack to compliment your first buy against the other type of damage .

Warmog is good against AP and gives you regen / randuin is good against auto attackers

Here you'll have to adapt your build to what you need the most

Need dmg ? Already have a full tank champ in the team?

Brk = good for mini gnar + active for dueling

Yomumu = great burst

Cleaver = good if your team is full AD

their team is ad heavy ?

Thornmail will counter AA champs

their team is ap heavy ?

solari = good against aoe

banshee = good if you must dodge an important spell

you just need to win the next teamfight ?

Take GA

The only strange choice is about E>W

Hyper is good , but is not really worth maxing early on , he will gain value as the game will last. You can max it 2nd if you really want to play an agressive lane

The E is good because you need to stick to your ennemies as MEGA GNAR , so the CD is invaluable here , and because it's a good steroid for mini gnar . Moreover you will build tanky , so more E is more damage from your health scaling ;)

Try to get level 2 just BEFORE your oppenent , but don't push the lane too much to do that , because top is very prone to early ganks .

As mini gnar : avoid direct engage using your range , use E to disengage (don't get it countered by a knock up) Q to slow and kite back while Hyper is activating . If your E goes on cooldown , you'll have to play VERY safely until he gets back again . USE Q TO LAST HIT IF IT IS DANGEROUS .

Your basic harass combo is AA>Q>AA or Q>AA>AA . Be aware of minions aggro dealing surprising amount of damage .

If you put your oppenent in kill windows with harass , be sure his jungler is not here and jump on top of him . You will slow him , get attack speed , and cut his escape route . Just proceed to auto attack him , Q him and ignite him to get the kill .

AS MEGA GNAR : Try to charge with a surprise double jump E , Q him then stun him into a wall , and use W to stun him once more , then Q again . You can put some basic attacks in between , and of course your ignite . Insane damages , trust me . don't forget you'll get movespeed at the end of your transformation .

Try to join fight at 90 rage , so you'll be able to transform "on demand" . Don't harass with Q or you'll transform for nothing . Wait for the right moment

As mini gnar: Really bad for your team , try to transform ASAP while kiting back with your carries and protect them !

AS MEGA GNAR : Get the double jump and GNAR them into the Wall then W on top of then a bit after (throw a Q inbetween) . If you suceed it's basically a won teamfight if the teams are even . Try to kill at least 1 carry with your full rotation , using trinity force and AA inbetween spells , it shouldn't be that hard. If you get CCeD or kited , don't follow unless your E or Q are coming back soon , it's worthless , go back and use your movespeed from transforming back to outplay them .