Sun but he's infected with Afton virus and basically replaces vanny. Vanessa a normal security guard and sun kills kids from his daycare. (Afton!Sun) or (AV au)
He would play hide and seek with chosen child so the parents can't find there child and suns like ¯\_(ツ)_/¯
Idk where they are. Daycare empty sun finds the child takes them to there studio?/ Room and chokes the child to death.
Sun eyes will turn purple and there pupils will be static red.
Bonus if like Sun gaslights Moon in to think he murdered the child and Sun acts innocent saying
" don't worry Moon,Sun here to help!" and does what every cyptic shit Afton want him to do with the body.
"You should really stop killing the kids you know?"
"You don't want to be scraped do you?"
"Oh lookie what a mess you made here Moon, now I guess I need to clean the giant mess you made"
Sun probably yell at Moon for mistakes he haven't even made and always blame him for things.
Also be a good reason for the finger prints on there body. The hands of the children trying escape Sun's grasp.