I love this build, early game Xin Zhao can steal some quick kills and late game he hits like such a truck you wouldnt believe

I chose armor pen runes for the obvious, I always find dodge helpful, that small percent may save your life a few times, and cooldown reduction to get charge up as often as possible.

Fairly self explained, I designed him to be all out offensive

Items are designed to have Xin hitting fast and hard with tons of life steal. Farm minions to build up bloodthirsters and watch enemies fall.
If tanks are hard to kill, consider replacing Infiniti Edge or a Bloodthirster with a MBR.