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).
Donatello is the ninja turtle wearing the purple mask. Don is named after Donato di NiccolÃ² di Betto Bardi and he is the brain of the group. He is very charming, but shy and slightly aloof and is also the least violent, but still kicks ass. He is the scientist, the inventor and the tech guru of the ninja turtles.