One image to sum up :

Story :

Throughout Valoran, the resolve of Demacia's military is alternately celebrated or despised, but always respected. Their ''zero tolerance'' moral code is strictly upheld by civilians and soldiers alike. In combat, this means Demacian troops may not make excuses, flee, or surrender under any circumstance. These principles are espoused to their forces by unrivaled demagogues who lead by example. Garen, the valiant warrior who bears the title ''the Might of Demacia'', is the paradigm to which these leaders are compared. Thousands of great heroes have risen and fallen on the bloody battlefields between Demacia and its preeminent rival, Noxus. It was beneath their mighty banners of war that Garen first met steel with Katarina, the Sinister Blade. The infantrymen who beheld this event (and survived) commented that it seemed as though the two were locked in a mortal waltz against a symphony of clashing blades.

Garen, the pride of the Demacian military and leader of the Dauntless Vanguard, returned from this battle breathless for the first time in his career, though some speculate that this was due to reasons other than exhaustion. The plausibility of these rumors was bolstered when, in every instance thereafter, Garen seized the opportunity to encounter the Sinister Blade again. A paragon of Demacian ethic, Garen never entertained such allegations, for he knew others couldn't understand. Even simply the pursuit of a worthy opponent on the battlefield is, to a true warrior, the reason to rise each morning. The promise of one, particularly so beautifully and diametrically opposed, is the validation of his existence.

''The most effective way to kill an opponent is to slice through the man next to him.'' - Garen, on front line strategy

Pros :
Amazing early burst damage
Great mobility
Great ultimate against Tanky champs
No cost on all spell
A great spell to tank ton of damage for 3 seconds

Cons :
Lacks of controls
Early kills dependent
Cooldowns are your nightmare

First item :

Doran's Blade

Core items :

Doran's Blade
Boots of Swiftness
Youmuu's Ghostblade
Frozen Mallet
Atma's Impaler
Infinity Edge

Sell your Doran's Blade and
Youmuu's Ghostblade to free 2 slots in your inventory for the second Infinity Edge and the situational item.

Late-game items : (Ultima DPS)

Boots of Swiftness
Frozen Mallet
Atma's Impaler
Infinity Edge
Infinity Edge

Late-game items : (Tanky DPS)

Mercury's Treads
Frozen Mallet
Atma's Impaler
Infinity Edge
Banshee's Veil

Last situational item :

Last Whisper
If they just stack armor to counter your insane DPS.

Guardian Angel
Guardian Angel has a great psychological impact on the enemy team, they won't focus you anymore and if they still do, your Carry AP should rape them.

Force of nature
A really good choice if you're playing against heavy carry AP for the magic resist. The movement speed passive is pretty fine to chase enemy too.

Randuin's Omen
I said in "Pros/Cons" that Garen lacks of controls, this item add you a bit of control with the slow with 1min cooldown.
This item adds health, armor and heatlh regeneration too. This is one of my favourite situational item.

Taric

Useful support : a great heal, a long range stun and an amazing Pink skin !
When he reaches level 6 he can also increase your Attack Damage.
What else would you like as partner ?!

Sion

An UNREAL burst damage if played AP and a stun. Added to your Judgment. Oh my god that's just awsome.

Blitzcrank

A pretty cool hook and stun. And a nice skin btw ...

Pantheon

A long range stun and a quite good burst damage with his Heartseeker Strike

Alistar

This cow can deal a ton of damage with some AP runes. Furthermore, he has an AoE stun with a great combo if he knows how to use his Headbutt and then mash the key for the Pulverize. Can heal aswell, not the best heal in the game but still a heal !

Lux

Deals a lot of damage and has the root with the longest range in the game. OP !

One of the best summoner spell to chase an enemy through the map coupled with Decisive strike

Exhaust

The spell to slow the enemy and lower his damage, then use your Judgment, you have scored a kill

Viable

Flash

Good choice against team with a lot of slows/roots. Useful when you're out of range to use Demacian Justice on a low-life enemy

If you did some nice game with this guide, just PM me your screenshots !

I'm thinking about some chapters to add but Garen doesn't need a lot of explanation, he's not really difficult to play. But if you want clarification about his gameplay, just leave a comment or send me a PM.

I hope you enjoyed reading this guide and you liked playing with this build. I'm really sorry if i made grammar or spelling mistakes but I'm swiss and English isn't my mother tongue so, just send me a private message if you find some.

Don't forget to leave a comment with some advices to increase this guide !