Very promising story.

If i can do a bit of light criticism, I'm a bit puzzled by the "display body in public" went out of the window immediately after the contract.
Especially as I think it might have been fun. I guess the Twitch idea kinda plays towards that.

Another concern was about him having visibly no qualms about leaving his DNA basically everywhere.

Finally, I think you easily could spend more time describing the action and the feelings and thoughts of the characters before and as he's killing them. Right now it might be a bit too heavy on the setup and a bit too clinical as a result. I'd enjoy something more personal.

Other than these 3 criticisms, I really enjoy reading you and I look forward to more.