This build is basically something I find fun, and it's actually rather good to use. The build is more for a self sufficient player, that helps your team kill off the enemies squishies. Yes, it might not be able to sustain a lot of damage, but played correctly with this build to weave in and out of fights properly help your team a lot. I've tried it plenty of times, and as long as your team is team based, this build won't fail you. Well, it hasn't for me at least.

The runes I have set up can obviously be manuevered. I tend to run the mana regen for early game killing because it helps, but i've also been debating on switching that over to magic resistance. That would help depending on what you're playing against or just in the long run, it's something i'm planning on trying out but in the end this might be the main build of it all. Since you're going to be doing plenty of burst damage on their squishies to not care TOO much about that extra magic resistance. Just don't bend on over for them and you shouldn't be in harms way.

My masteries I have put out are mainly for starting roles and the extra HP pool. Since the masteries are based to help my HP, as well as my damage of course, i switch my runes to mana to get a little help in both area's. This helps me survive early fights to get the first kill, first kill assist, or to get away in fights with enough health to keep me alive from their ignite.

Yes, the item display may seem like it's pretty random, but i've tried it around. The extra HP from the hammer at the end is just a bonus, especially with the life steal you will have from the bloodthirsters will be plenty to keep you alive in certain combat. As long as you don't get rushed, ganked, or caught off guard in the jungle you will be good. It also gives you extra slow added with a skill already to assure they don't escape.

Taste their fear will be your main skill, followed by Void spike, then Leap. Of course you'll be grabbing your ultimate when you can, and with this you'll in the same order evolve those three skills. I don't evolve my ultimate because it's not fully needed.

Basically, in the beginning of the fight you're just going to continue staying top. Laning is nothing special since it's the obvious. Now, the only way I tend to play Kha'Zix is an assassin type. I never run with the team, though I always stay close. Never creep to far in the jungle because if you do, you never have the time to make it in for the kill. You save your ultimate for just the right moment when the enemies range adc or a squishy backs up just enough away from the team to give your taste their fear that extra damage. That'll pretty much assure you a kill, leaving you to use your ultimate one last time to creep back away. The leap, of course resets due to kills. So you'll have that again after you go in for the kill to have an escape. Pretty much you'll rinse and repeat. The other team might QQ because you're not playing with a pair of balls, but they will be dead so it doesn't matter. now this build will help keep you alive in some fighting scene's but make sure you choose wisely. Things can and will beat you down, so play smart. You will always want to get the first hit off, leaving them really low on HP before they even have a chance to get you.
That leap of yours, i never use for initiating a fight. Unless they do not have two means of escape. If they just have flash, you'll have two ways to catch them, if it's someone like ezreal you'll have to save that leap for when he flashes twice away from you.

Play this build correctly, and you'll learn to enjoy it. In the end, you'll play like a true jungler, a true assassin, someone the enemy will want to look out for.

In the end, this build is mainly for being the assassin of your team. To help rid of the ad caries of the other team while they take quick runs to escape. They may want to run back to let their tanks get ahead of them, and that three seconds to five gives you plenty of time to rush in, burst damage them leaving them just barely living, or dead. Either way, they are out of the fight. Try it out, give me your thoughts. I'd like some input and to see what you've guys thought of it, or have done with it.