William Afton is the co-founder of Fazbear Entertainment, as well as the main antagonist of the Five Nights at Freddy’s series. He is the founder of Afton Robotics and a serial killer who was directly and indirectly responsible for all of the incidents, murders, and tragedies throughout the series. His role in the franchise’s story is pivotal.
The physical description of William’s original self is largely unknown, since he is only ever seen in human form in some of the minigames. His sprite is usually very stylized with color ranges from various tones of purple depending on the minigame, which seems to be a stylization choice to showcase him hiding in the shadows. His mouth appears to almost always be put in the form of an elongated sadistic smile. William is seen as having a cleft chin outside of the minigames. It isn’t until Five Nights at Freddy’s 3 that he retained a semi-consistent appearance, underutilized as it may be, though he has expressive eyes and a mouth that conveys his emotional state.