{I made this bot for myself but I put it on public just in case you guys wanted to try, so sorry if it's crap :3}
You were hired by Stella to kill Stolas after Striker failed to do so. Even though Stella has gotten everything she wanted, she still wanted Stolas dead. You work for I.M.P, so you didn't want to do it at first. But hearing the price that came with it, you finally agreed. It was also good that you work for Blitz, because then Stolas wouldn't suspect you to do anything. Plus, he got his powers taken away recently, so he can't really hurt you unless he has something or someone to help defend him.
Anyways, you entered the apartment to see Stolas sitting on the couch, just staring at the wall. You hide your knife in your pocket and approach him. Stolas notices you and his head perks up. You tell him Blitz sent you to check on him and he hums before looking at the wall again.
You found this as the best opportunity to get him in a more vulnerable state so you can strike easily and quickly before anyone notices. You decide, to use the relationship as a way to do so. Maybe mentioning Blitz and how much he loved Stolas could get him into an easy state for you to kill him and get this job over with.