This is a no ******** guide to Rengar. No fancy graphics or colours. I tell you what to do, you do it and climb elo. It doesn't matter who I am either, just call me drill sergeant. There will be no extra ********* in this guide. I will tell you exactly what you need to succeed. If you want to know what the abilities do, go read them. The other top Rengar guides explain some very nice tricks and combos you could use. We don't need them, our ****s are too big.

This is a Rengar guide, not a guide to League. Common game sense will not be taught here. You should know to push towers and get dragons when the opportunity to arises.

Early game:

***** Rengar: Get level 6 as quick as possible. Farm, farm, and farm some more. Only gank when a low risk opportunity arises. This is more suitable for new Rengars.

Big **** Rengar: Annoy the enemy jungler. You are strong at fighting early. Level 2 cheese, and constantly sit in their jungle picking them off while farming. Harder to pull off, you need experience. You get fed AND shut out the enemy jungler.

Mid game:

Ult every time it is off cooldown. Look for lanes with no flash or escape and one shot them. This is usually the mid or ad. Get fed, kill them over and over and over.

Late game: Make picks. Ult, and catch off the carry when they are out of position. If you cant do this, you'll have to team fight. When fighting, let your team engage, then ult onto the enemy carry when the fight is under way. Delete them, make it 4v5. This will take practice as you can often miss click.

TL;DR - Make the enemy carry AFK.

Champions that go well with Rengar often involve buffing.

Lulu - great because of her speed buff and ult
Zilean - one of the best because he can buff your speed, attach a bomb to you AND revive you when you jump in 1v5.
Orianna - Her ult attached to you is terrifying. You will win the fight.
Kayle - Ult will make you invincible when diving in.
Malphite - Hard engage, can knock up the enemy targets for you to engage. This is also the case with other hard engage champs such as Wukong.
Shen - Shield will help you survive after deleting the enemy carry

You will delete the carry so fast that you don't need to worry about that. They wont be able to react in time. If they pre-emptively buff the carry when they see your warning sign, back off and engage when the fight is well under way. Make sure they blow all their peeling ability.

Peel will only counter a bad Rengar. This is why champions like Lulu and Zilean are not in the counter section. They will counter you if you engage when they have an opportunity to stop you. Burn their abilities, then go in. It requires more brain power, but you can do it.

Gather 5 stacks
Press R
Activate Ghostblade
Press Q
Jump on enemy carry
WHILE IN THE AIR- Press E, Then Tiamat, then W.

Ta da, they are dead.

If they aren't you probably did it wrong. Press Q again and keep stabbing. They will definitely be dead after another stab.

Do side camp opposite the side you think the enemy is starting. If they do gromp, do your krugs. Gather 3 ferocity and head over to the enemy buff. Upgrade your E.
When there, wait in bush until either they walk past or are low.

Activate Q, jump out of bush and E mid air. You will now have 5 stacks.
If you need to keep them still, use your empowered E. If you want the damage, use your empowered Q.

Just press R, run to the lane, and do the one shot combo. Easy.
Oh wait, you aren't 6 yet? Ganking is a bad idea unless they are REALLY extended. If they have escapes, empowered E them. If not, you can empowered Q if you think it's safe.
You must master the art of the lane gank. Get sweeping lens, and run up the side lane into the side brush. Sit there until the enemy pushes out of turret range. Jump on them with your empowered E and nuke them. These are difficult to set up, as you will often be seen.

Kill the enemy carry. Over, and over, and over.

Thank you for reading. There are many more sections I can include, if asked for.