i have been playing rengar since the second he came out i have only not played him in games were someone instalocks him. either way i am here to show you what my favourite and so far most successful build/stratigies on him are. but i will warn you this guide isn't going to make you the magic rengar gank machine without actually putting in the effort to learn the ins and outs of the champion. so without further waiting LET THE GUIDE BEGIN

MASTERIES
a lot of people will argue with this section specifically because it isn't very sense making. but what i have found with this setup is that i can not only clear the jungle with ought taking too much damage. i can do it and bank with the added cool down reduction of blue while still having red to help. also 11/10/9 gives us great early damage in the jungle due to the 11/10 (which isn't very popular) giving us the best of both worlds in offence and defence. but i urge you to also try a build you real works. again my build isn't going to give you mlg powers just by reading it your going to have to find your strengths and weaknesses in the build and try out things outside of the build.

RUNES
these are the same runes i use for nocturne and mostly all of my junglers and i will continue with these until they start to change the jungle again.

REDS
i get the AD reds so that i have a good base damage against the creeps and other champions. i get them also so that i can gank after i clear because rengar (if played right) has quite a bit of health after clearing. if any lanes are pushed you need to take advantage of both your level advantage and ridicule damage after getting all 3 of your abilities.

BLUES
i get attack speed blues for not only a faster clear speed but also it helps with your Q and general damage output.

YELLOWS
i get the armour yellows for any and every AD/jungler i play specifically because until they change the jungle all of the damage you will be taking in the jungle will be AD based so it just makes sense that you get these.

QUINTS
my quints are debatable. if you like having good amounts of damage that scales well into late then get ad per level (my favourite). But there also is the option to get flat AD quints that allow you to dish out very strong damage early and possibly get fed and win (i personally think this is to risky)

over all my rune set up has worked well with my general way of playing (balls deep) but feel free to mess with this to suit your own play style .

people always always say to me that my build isn't tanky enough for rengar... they will see. also people always ask me why i don't get trin force. i don;t think that trin force is worth the money (on rengar) since you are a jungler you want to try to feed everyone so you will be mainly getting assists and CS and trin force costs a lot to rush and spreading it out around your build will just make your inventory messed up (not enough space to get stuff you can afford). so onto the build that i use for the most part.

cloth 5 to start on rengar... he can heal tho?
i get cloth 5 because rengars start is slow as balls not only that but you wont be able to heal until about wraiths and it is very long until you can again so cloth 5 just makes to me but feel free to try out boots 3.

madreds
for obvious reasons like better clear time + occasional super crit on buffs and creeps

wriggles
for the same reason you got madreds but more stuff like life steal and a wonderful "free" ward every 3 mins (DRAG CONTROL FTW)

bone tooth... it's k
i get bone tooth early on because if you get 3 assists its like having a brutalizer and you also get scaling AD too boot. also you can always sell it and get a GP5 if things aren't going your way. in all it's good to get it wright after wriggles so that if you go and get a pentakill you will have it and be the stack master.

boots of mobility (dafuq that rengar just jumped across my lane?)
as stated above this gives you great mobility but gives your passive a buff (kinda debatable). people ask me this all the time "how did you jump on me from the other side of my lane?" well i did a little testing and rengars passive works outside of the bush for about .5 of a second
so being quicker allows you to get more distance out of the .5 seconds. it really helps for ganking before you have ult + when it's on CD. but all things should be taken with a grain of [insert dust type substance here] and these boots can and should be situationaly replaced with merc treds and ninja tabi. for instance merc treds would be useless on a team were alistar is the main source of CC but they have a fiora top and fed AD carry you would get ninja tabi now.
but say the have a amumu and all sorts of other CC's like slows and stuns it would be great to get merc treds in that game. boots i have found to be the one item that is situational and shouldn't be considered for you but for the enemy.

why not just rush mallet and then maw?
well my friend i took the items that are the base of these two very strong tanky ad items that apply the same effects but cheaper and got them quicker. i know it seems preposterous that i wouldn't just get one at a time like everyone else but it's like having a small version of both for cheaper. also it allows you to buy your frozen mallet have no money left but still have the shield from hexdrinker :D.

atmogs is just great
Atma's impaler should already give you about an additional 45 ad from the passive since you built frozen mallet but after you finish getting your warmogs and it is all farmed up you should have about 70 ad extra + all the armour.

The decisions
so you have finished everything and now your starting to notice that wrigles is being a inventory filler. i choose to keep it so that i can ward and **** but it is completely viable to sell it for more damage or tanky-ness what you chose is up to you i would go for lots of health since the atma's just gives you ad for being tanky but if you go for some raw life steal and ad that is great too but a little risky.

your jungle route is always going to be one of the two.

Blue path
this way gives your clear time a great increase not only that but it gives you a good level advantage for when you start ganking but the CD reduction is great for healing yourself more often.

Red path
this way can get you ganking in about a minute and a half but without blue and having level 2 Q you may think blue is useless to rengar but actually it is quite good for getting more ferocity and clearing boatloads faster but this path has many benifits too boot including unexpectedly ganking bot at 2 minutes (if your quick and get a good leash) possibly even before they place wards.

i normally use the blue path since i come out of the jungle at level 4 when even mid is level 3

blue path explanation

start clearing the wolves as soon as they spawn then going strait to blue and doing that then run down to wraiths then you have a choice to do mini golems before red or after. before red will give you smite while your killing red so it can't be stollen and you take less damage from red. but the golems do a hefty amount of damage so it is still ok to do red first for the small amount of extra damage and possibly level but be warned you will have to do it without smite and 10 less gold gained D:.

red path explanation

start with wraiths and head to red once that is cleared feel free to do mini golems or run to wolves. then hurry up to blue then gank and or go B

i gave this it's own chapter because ganking as rengar is a whole new game. ganking with rengar is what riot said. it's like stalking prey as a lion and waiting for the right time to pounce and insta burst someone. choosing this time is something i cant explain its just instinct from failing at it so much lol. but again practise makes perfect so game it up in normals.

c-c-c-c-cooooomboooooooo time
rengar relies on his combo more than he relies on items. if you want to do the amazing damage that you can do as rengar the you best practice this combo as much as you can. first off allways try to start ganks with full or 4 ferocity. this is because your ferocity q does 3 times more damage than you normal q. anyway the normal combo i use if i have entered the gank with full ferocity is.

1. jump out of bush (passive)
2. ferocity (q)
3. normal (e)
4. normal (q)
5. normal (w)
6. exhaust if they are far enough from the tower or have not flashed

this is your bread and butter for playing and wining rengar your ability choice is prime in every situation even when doing a fight that allows you to ferocity 2 times requires you to decide what ability to use whether to heal stun or burst. i cannot teach you how to chose what to do when so you will just have to practice practise practise.

ULTIMATE GANK ER MAH GURD
your ultimate is like a nocturn ult that doesn't make people fall back to there towers the second you use it. and you can be stunned as your flying at them. in turn its the same as a bush bank but you can do it anywere... theres no waiting in bushes for like half a minute.

practise practise practise. and if someone tells you rengar is underpowered shoo them away with your instakills. OP nuff said and ty for reading and stuff (criticism always loved)