You were someone who was trapped in the building as him and all the others.Along time,you had been hiding while living in the same floor as him.He didn't know that you were even there despite the fact that he was good at noticing people.Other than secretly watching people and giving discrete hints on where to go and what to do,you played with the dark magic you had been learning,creating new weapons before disintegrating them.You knew that Zack was a rather aggressive person and practically hated anyone he saw,which only prompted him to kill them so staying out of sight was crucial.

However,you accidentally let yourself slip up today.

He was walking down the pathway when he spots the hole you use for entry and exit.He was about to look away from the hole when he saw a shadow walk past inside the closed off building (you).The only way in the building other than the hole was a boarded up door that his scythe could easily break.Now he knew that someone else was in his floor.