Not Updated For Current Season
The masteries shown here are not yet updated for the current season, the guide author needs to set up the new masteries. As such, they will be different than the masteries you see in-game.
Build for Fun/ Braking the meta.
Garen The Might of Demacia.
He really is a champion that deserve a respect. Going tanky with him, choosing Black Cleaver is a really big deal.
You can go other way, much more harder and funnier way.
Where every AD carry, will be afaid of your hit, and Evry squishy mage will tremble and soil themself in the mid lane after hearing "DEMACIA" call!
You need to beware of Jungle, aviod this lane with this build or customize runes for doing it.
General tactic is - Farm minions as you can, sit in bush and attack with Q when someone will come close then Spin and Q again. For secure kill Ignite.
Have Fun ;)