G'Day Everyone.
This is a guide for a top lane, assassin, dueler Kha'Zix. He is a strong champion in the top lane as he can clear well and as excellent 1v1 potential. You should play Kha'Zix in a ranked situation when an assassin is needed and when you already have a tank. Hope you enjoy and learn from my guide.

Standard Masteries for an AD top. Butcher for easier farming. Blade Weaving and Spell Weaving as Kha'zix relies on his spells for max damage and as his Q his on a very short cooldown, it allows max damage.

Again Standard runes for an AD top. Armour Pen Quints interchangeable with Flat or Scaling AD.

Pros

Amazing burst
Excellent Duelist
Resets
Short Cooldowns
Easy farm

Cons

Often targeted in team fights
Fragile
Short Range
Good positioning
High Skill cap

One of Kha'Zix unique attributes is the passive of his ultimate. This allows him to add an additional effect to a spell every time Kha'Zix hits level 6/11/16.

Evolve Q first for max damage and dueling. Then E for range and team fights. Then it depends, if you need clear speed get W but if you need more potency in team fights, I recommend R.

Starting with a long sword I have found to be most efficient as it builds into other core items and gives max damage at early levels.

Most of the time, rushing a Brutalizer is best but make a judgement on what you are trying to do in your lane. If your team needs you to push, rush a tiamat.

Frozen Mallet if you need more health and Maw of Malmortius against AP heavy team.