A Vile Vermin

Hi,

I've been playing POE for a long time, but can only ever be casual as I have too many RL responsibilities in consideration, however;

I've always been intrigued by certain areas in the game and had it as a fantasy to take these venues as starting grounds for character creation.

Long story short, I'm thinking of a Shadow creeping out of the sewers and crevices in Sarn with all the filth and stink that goes with him. The one that Hargan warns you to, "stay out of the shadows, they bite." I'd love to create a character that has shadow and poison on his side. Perhaps a poison/chaos flicker with retaliating curses? Doesn't need to be a serious serious contender for build of the week, just a project... but I don't know where to start.

I've been searching the forums and youtube, but can't seem to find anything resembling a viable 3.22 kind of build. Any suggestions?