PoE Nithryok builds

So i stopped playing poe this league about a month ago, but got high tonight and decided to theory craft something. any further ideas on how to make it tankier? Keep in mind this is for a HC sudo starter build for next league. how does alchemist mark feel for clear? Edit: ignore I forgot to finish ailment avoidance on gear.

Edited updated build I have made this build, please tell me what you think. The goal was decent regen, leech, high dps, chaos convert so we don't have to worry about pen. The gear in the build is not great, but decent and easy enough to currently get for cheap.