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).
Purple Shep is the son of Pink Sheep and The Enderdragon. Purple Shep, sometimes mistakenly called Purple Sheep, has the body of a generic sheep, with thick purple wool and hooves. However, his face is the weirdest feature of his body, as the face is extremely messed up and ugly. The only feature similar to Pink Sheep is his naturally well-trimmed mustache.