This is my short guide to jungle Kha'Zix. For this guide, I focus on damage, with a good amount of tankiness, to be able to jump in and out of fights to pick off high-priority targets.

The runes I take focus on damage and armor, with a little attack speed. This allows for faster clearing time, while not taking too much damage. Health and magic resist can be applied as well.

The masteries I chose focus on damage and durability. As said before, this is to speed up clear time and create successful ganks. For this build, I would stay mainly in either the defense or offense tree.

Start out with Hunter's Machete and five Health Potions. This will help clear time and keep your health high for ganks. Quickly build into either spirit of the lizard elder or spirit of the ancient golem]]. Another good item to gain a bit of lifesteal and armor from is Wriggle's Lantern. Any of these items is a must have for Kha'Zix. In my eyes, Trinity Force is a spectacular item for Kha'Zix. It gives great all around stats, and increases movement speed. Maw of Malmortius adds in much needed magic resist and damage. Frozen Mallet gives tons of health, and allows you to stay on a high-priority target. With all the damage you have, Ravenous Hydra is a good choice, since you probably will be in the middle of a teamfight most of the time. Any other mix of damage or durability is good with Kha'Zix, so don't be afraid to change it up.

Usually, you will want to max Taste Their Fear first, Void Spike second, and Leap last. At levels 6, 11, and 16, put a point in Void Assault. After each point in Void Assault, you will get to evolve on of your four abilities. I usually evolve Taste Their Fear first for increased damage, then either Leap or Void Assault second. Evolving Leap second is nice if you feel like you can secure a kill, because after it is evolved, if you get a kill or an assist, the cooldown resets, allowing you to continue chasing. This works great with Frozen Mallet, allowing you to pick off easy kills, or slow them down enough to let your team come and secure the kill.

When going for ganks, try to land right on top of the enemy with your Leap, as it will deal a good amount of damage, and set you up for a Taste Their Fear. Try also to counter-jungle depending on who the opposing jungler is. Save your Leap just in case someone shows up while you are counter-jungling. Roam around a little after ganks to try to catch someone out of position, as Kha'Zix is a great 1 on 1 champ, because of Taste Their Fear. Use your ultimate wisely, either to gank, or jump on a squishy target in teamfights.

Have fun playing Kha'Zix, he's fast and agile, and kill that Rengar for a little surprise.