hi i know this is a new champ but ive been using this build and it is really effective so far, my first time using this build i got 25/9/17 and we won too which is the most important part, this build was not built with jungling in mind, yes i know hes a jungler but this is more for the lane but ive had a friend test this build in the jungle and he said it also worked for him so i hope it helps, i wanted to build this with magic pen in mind because its always good to get the best of both worlds while still having survivability, its great late game and pushing lanes specially with that attack speed and his Q ability, when you have full ferocity with the Q you eat away health like no tomorrow. before you reach the phage if you want to throw in the bonetooth necklace then be my guess i left a space for that but if you dont want to then i would buy a bloodthrister or a maw of malmortius even go for an infinity edge to finish the build but its completely up to you and how you play, hope this helps and feel free to send your feedback. i welcome all comments to try and make this build better and more dynamic, thank you :)

for the second build add the bonetooth necklace after you have the heart of gold if you want to take that option. that is for the solo top or tanky players. ive added two boots to give you a choice depending on the opposing team. hope you enjoy my builds and they help you out and all feedback is welcome :)

Pro's:
great burst damage
great farm
passive is great for ganking
a pro jungler
excellent ganker
great damage early game and a strong overall game

Con's:
squishy early game compared to other AD champions
R is his only escape mech
hes lost an eye :(
his ultimate can be countered by wards

in team fights rengar's role is to stealth in with his R and take out the enemy teams carry, build up as much of his veroscity as possible, if you manage to take down the carry (depending on how good the team around you is) then move on to the more squishier targets etc a teemo. if you came up against a darius, wukong or lee sin, then they will be the ones to focus first then someone like a teemo, twitch, kog maw.