Welcome to my Jungle Rengar build! This is my first build but that doesn't really matter (or so I hope) so I'll just get right to it!

On-the-Side:
Rengar; the name can be defined in welsh as bookish, tempting, alluring or charming. So essentially, according to the Welsh language and Google translate (whose credibility cannot be validated), Rengar should be an intelligent beast who lures you in with his good charm and looks...Well dang that really doesn't fit him at all... Oh well! On we go!

Pros:

-Easy to jungle with early game
-You can jump out of bushes!
-You're playing a freaking lion-man!
-Amazing and versatile ganks with a root/burst
-Crazy burst potential through to late game
-He even use's a freaking knife and claws!
-Ultimate to scout out missing enemies and counter gank
-Uses freaking bolas to slow/snare enemies trying to escape!
-Nearly impossible to gank with regular use of ultimate when unneeded

Cons:

-He's extremely susceptible to counter-jungling
-Is squishy when focused in teamfights
-Vulnerable to Crowd Control effects, esp. silences/stuns
-If you are denied jungle kills, things can go downhill fast

My preferred jungling path is to start with the Wolves (which, with my build will bring you to 4/5 ferocity) then head over to Blue, proc your Q and jump in, using your Q immediately after landing, using smite when necessary. By that time you should have another skill, which personally I like to get Battle Roar for the heal. At this point, you should have 2 potions remaining. At this point I recommend getting wraiths, then Red (if smite isn't up, grabbing the Golems before hand), and if not previously killed, the Golems. After that, usually things screw up in top lane (I have a bad experience with horrible solo-toppers) and I'm left to help top lane, if not; continue jungling back up towards Blue, until you gather enough money for your next item; Madred's Razors. At this point, I feel I shouldn't be telling you what to do and instead figuring out where to go from there. (And if your solo top or mid is a mana-hungry champ, offer up Blue as needed)

I'm honestly, too lazy to figure out how to do a full template for this whole 'item section' with icons and cool headings and all that, but aside to the build order stated above, I would like to mention other viable items for Rengar;

Atmogs (Atma's Impaler/Warmogs)
Frozen Mallet
Sword of the Occult
Maw of Malmortius
Banshee's Veil

There! that's it. Told you I was lazy.

I don't know what you may think about my build order/particular items or my tactics, but my main purpose with this build is to create a jungler (who excels at not only "jungling" creeps, but also at helping pushed lanes) who is capable of also being a strong late game AD burst to take out critical targets and towers with ease.

There you have it! Goodbye for now! :D