They say it can't be done... that he is not viable... Well I'm here to prove I can do it with high wins rates.

PROS
-Heavy dmg throughout game
-Great mobility and fast clear rates after leveling
-AP and ADC characters will fear you
-Can tank baron easily and eventually even solo

CONS
-Slow jungling start and easy to fall behind *You Have Be Forewarned*
(Just make sure to stick to the pathing the best you can or find a way to catch up if falling behind.)
-CC is your weakness. If you face some CC get a quicksilver sash.
-Fairly tanky but not able to do much without a team unless 1v1.

By level 6-7, you should have bilgewater and ganking easy. Before level 6, it is possible to gank but is harder without bilgewater. Once you farm up to cloak of agilty you will be able to solo dragon. After infinity edge, you will crit for 660+ on normal hits and 950+ on garen strike. Finish off with a phantom dancer for the movement speed and great crit rates. All other item are optional. I would consider atma impaler, another phantom dancer, the black cleaver, last whisper, frozen mallet, bloodthirster, ghostblade, quicksilver, or even a tiamat. It all depends on each game.

You start at red and get a leash from someone. Go for wraiths and if you can wolves (wolves depends how well you got leashed. Tp back to base, heal, and head back for wraiths again. At this point you will be lvl 3 and golems will be a breezes with smite. Tp back to base and get vampiric scepter. Kill blue or give it to your ap mid and then conitue to kill the rest of the jungle. Tp and get boots. Start wolves and make your way towards golems picking up red again and reaching level 5. Too bad you have to tp again for health. This round you could gank with red, or continue farming till you reach 6+ and bilgewater. Afterwards gank as much as you can, but cotinue to farm your way to taking dragon. From there the world is your oyster.