In some ancient civilizations the Wolf was a symbol of the underworld. In Egypt, the guardian of the dead was Anubis who was a wolf-headed god. The jackal portrayed as black was the symbol of both death and regeneration.
William is also the one who hid inside the suits and kidnapped and killed children, leading to the assumption that William Afton is The Purple Guy of FNaF 2 and 3 (he is killed at the end of the book when Charlie sets off the spring locks in his suit).
Fnaf Sister Location Fan Made 2. Fnaf Sister Location fan made 2 is worth a try if you are a big fan of this kind of new horror game made by Scott Cawthon. At the moment, you can check out the demo versions of Fnaf Sister Location created by a fan. This is one of the best fanmade FNaF games that you should explore.