Hey MOBAfire,
Since Gnar was released he has been my favourite champion and has inspired me to join MOBAfire. Gnar is a strong mid-late game champ who, if played correctly can also be a pain in laning. This is my first guide on MOBAfire so I'd be happy to know how I can improve in the comments. Hope you enjoy.

Amazing Mid Game
Has a crazy amount of poke and mobility in mini gnar
Surprising amount of cc
Good burst for a tank in mega gnar
Riot might one day make a baGNARna skin

Not great laning phase
Squishy in mini gnar early game
Poor mobility in mega gnar
Has a lot of counters

Now you might be thinking " Why are you building flat health instead of scaling health for a mid-late game champion? ", Well, simply, to survive and possibly even win lane, this will put you ahead so that you can make up that health in items. The attack speed quints work greatly with your W so that you can apply hyper faster dealing more damage then just AD quints or marks and that attack speed will go well with the ARPEN marks.

I see a lot of people running much more offensive 21/9/0 masteries on gnar, and you could do that, I just find that a tanky gnar is much more useful as he can still deal a fair amount of damage, but an offensive gnar won't be able to tank. ( You can switch the 3 points in hardiness to 3 points is resistance if you're laning against an AP champion ).

Rage gene: Passive

Basically whenever you deal or take damage a meter fills up ( your rage meter ) and when it reaches 100 you turn into Mega Gnar.

Boomerang throw/ Boulder toss: Q

Boomerang throw is a skillshot that deals damage and slows it also applies a stack of hyper but then it will come back in the direction you were running when you threw it if you catch it you will massively reduce the ridiculous cooldown it has, try and poke with this whenever you can. Boulder toss is a skillshot that deals damage and slows but instead of the boulder coming back to you it stays there and if you walk over the spot where it stopped it will reduce the cooldown.

Hyper/ Wallop: W

Hyper is a stacking ability that means every three auto attacks on the same target in a short time and you will deal bonus damage and get a speed boost for a short time. NOTE: You do not stack hyper while in mega gnar. Wallop is and AoE ability that,after a short delay, deals damage and stuns all enemies in a rectangle in front of you, this is a great ability to use in teamfights and can give you enough time to position yourself for your R.

Hop/ Crunch: E

Hop is a short range jump, but, if you land on a minion or champion ( enemy or ally ) you do a second jump in the same direction as the first hop it also slows whatever you landed on with your first jump. Crunch is also a short range jump but unless you use it to transfrom into mega gnar you won't do a second jump. It also slows in an AoE.

GNAR!: R

In mini gnar GNAR! just increases hypers movement speed boost, but in mega gnar it will knock all enemies in the AoE the way you're facing dealing damage and slowing them, but if the enemies hit terrain they will be dealt increased damage and will be stunned. Always try to knock enemies into walls when you use GNAR!

E ( transform into mega gnar ), R ( into a wall ), Q, W
This is your main kill combo, it probably won't be enough if they are full health so try to poke down with your Q when your in mini gnar.

Q ( collect boulder ), Q ( collect boulder ), Q ( collect boulder ), E, W
This is how you chase as mega gnar, mini gnar is just as easy. Throw boomerang, catch boomerang, get hyper, catch them.

Flash

I always take flash on gnar. I just prefer it to ghost and it can be used with hop to get 3 small jumps.

Teleport

Teleport is a good spell on gnar, you can tp back to your lane and not lose any cs after you have gone back to the shop. You can also teleport to ward in another lane for a surprise gank.

Ghost

Like i said, you can take this or flash i just prefer flash because it combos really well with hop.

Ignite

I usually take ignite if i'm looking for first blood. Unfortunately you will almost never get first blood if you are gnar, so unless you are up against nasus or rumble take something else.

Clarity

You have no mana so don't take it. Pretty simple.

Barrier

Barrier sort of becomes redundant later in the game because you'll be so tanky the shield it gives you will seem tiny.

Heal

I guess you could take heal on gnar, but usually a support or ADC will take this and it's more important for their heal to get off max healing rather than you.

Revive

I never take this. Ever. It means that you plan on dying.

Exhaust

Usually a support spell but you could take it if you plan some assasin gnar shenanigans.

Cleanse

If you are being cced too much just get merc treads or Quicksilver sash

Clairvoyance

This really should only be used if you have a global ulti or are a support.

Mini Gnar

As mini gnar your role in team fights is to become mega gnar, through auto attacks and boomerang throw then jump in as mega gnar. Attack whoever is coming towards your ADC.

Mega Gnar

Mega gnar is great in team fights, you should try to be the one soaking up the damage from there carries. In team fights ult the enemy team ( prioritise the carries ) into a wall then Q and W them all. If they lock down your ADC you can either ult them away from your carry or Q and W as much as you can and hope that the carry can run away.

Thank-you for reading my tanky gnar guide it has worked for me so far and I hope it works for you. Gnar is such a fun champ to play, I'm sure you'll get the same enjoyment i do out of him. Please feel free to leave constructive criticism below.

JayFubble.