Since pre seascon 3 has been released the whole store got revamped. With the revamp of Black Cleaver riot gave ad bruisers a huge buff. But how about stacking it, getting 40% cdr, 1k hp and tons of damage? Especially on Garen, who has no mana issues. In this guide I will show you, how awesome Cleaver Garen can be.

Black Cleaver got a nerf, so stacking it isn't viable anymore.
The new build still focus on getting tons of arm pen and dealing full damage with physical
attacks and abilities. Please read the full guide and try it out, before you vote! -
Don't forget that a guide doesn't ensure awesome stats, but may give better overall score.

This guide isn't finished yet. If you have any ideas post them!

+ sustain due Perseverance + tanky due Courage + high mobility due Decisive Strike + Demacian Justice FINISH HIM!

- damage falls off in lategame - also useful if build tanky - Decisive Strike only source of cc - Demacian Justice deals magic damage

Greater Mark of Armor Penetration increase your damage output during every stage in the game.
Greater Seal of Armor makes laning against AD bruisers easier.
Greater Glyph of Scaling Magic Resist you don't need Greater Glyph of Magic Resist vs AD
Greater Quintessence of Armor Penetration same as Greater Mark of Penetration but bigger!

Other viable runes are:

Wash away the cc! Awesome for escaping and getting the enemies carry. Nice synergy with Cleanse. Awesome chase and escape tool. Shut down the enemies AD carry or just prevent an enemy from escaping. Good for baiting and surviving! Great synergy with Courage! You just need this against Dr. Mundo! Nice escape tool, especially against Jarvan IV's Cataclysm!

Perseverance is a awesome passive! It just give you tons of sustain for laning!

Decisive Strike is your initiation spell. It grants a Mini Ghost, a Cleanse against slows, increased damage and silence on your next attack. Use it for harassing, initiating and escaping from ganks.

Courage is the source of Garen's durability. It grants increasedarmor and magic resistance, but also reduce received damage and cc for a short duration. Use it when you receive burst damage, like during ganks, tower dives or when you are focused during team fights.

Judgment! Spin to the win! Nice farming ability with great earlgame damage. Use it in the lategame to damage multiple enemies at once.

Demacian Justice is your finisher. It deals damage depending how low your enemy is and has decent range. But don't forget that this ability deals magic damage. So if your enemy has tons of magic resistance this ultimate wont hurt him alot.

Boots + Health Potion
Since your AD ratios are weak at the beginning and your Judgment can't hurt enemies, that are faster than you! You should really start with Boots.

Doran's Blade
Cost efficient item, that restores 5 hp whenever you hit an enemy.
It makes your earlgame even stronger and your sustain even better!

Boots of Swiftness
Gets you faster to the enemy carry, makes hitting with Judgment better and reduce slows, what is very important to counter kiting! You can replace this boots with Ninja Tabi or Mercury's Treads depending on the enemy team.

Black Cleaver
The revamp of this item is so awesome for Garen.
It provides every stat you need and the armor debuff is also applied by you Judgment!
If you get 4 of them you get 1000 health, 220 AD, 40% cdr, 60 arm pen and get all 4 stacks of the debuff instantly on your enemies! This makes it very easy together with your 19 arm pen from runes to deal true damage against a carry.

Guardian Angel
This item provides a average amount of armor and magic resistance and has a nice passive.
This passive makes focussing you during teamfights less viable, while the active is ready.
So the enemy team wont focus you, unless they really want to take the passive from you.

With your full build you will archieve roughly 300 AD and 49 arm pen.
A common AD carry like Ashe has 73 armor at lvl 18 and
with flat armor around 86 armor.
86 armor - 25% Black Cleaver makes 65 armor.
65 armor - 43% from Weapon Expertise and Last Whisper makes around 37 armor.
Since we have 49 arm pen we will deal true damage with our Q, E and autoattacks.

Well nearly every AD carry gets a Guardian Angel so the may have 50 additional armor.
86 + 50 armor makes 136 armor.
((136 - 25%) - 43%) - 49 makes 9 armor.
What makes around 8% reduced physical damage.
If the enemy team has a Runic Bulwark or a Aegis of the Legion,
they will have additional 10 armor, what doesn't change alot.
But it will still increase the armor of the carry by 4.

Since you have around 300 AD at the end your abilities will really hurt!

Decisive Strike
Deals 130 + 1,4 x 300 physical damage on the next attack.
What makes 550 physical damage!

Judgment
Deals 120 + 1,1 x 300 physical damage every second to enemies in 330 range!
What makes 450 dps for 3 seconds. So it deals 1350 damage over it's full duration!

With your Q & E combo you deal up to 1900 physical damage over 3 seconds.
This might get the enemies carry low enough to finish him off with Demacian Justice!

Special thanks @ jhoijhoi for her guide! You can find it here http://www.mobafire.com/league-of-legends/build/making-a-guide-101506 !