Circus Baby (or just Baby for short) is the star of a closed down spinoff of Freddy Fazbear's Pizza named Circus Baby's Pizza World. It closed down after Baby kidnapped and killed William Afton's daughter.
Baby has red hair, a red dress, red blush, red pointed-toed shoes and a red microphone. She also has purple eyeshadow on the channel, though ingame-canon doesn't feature this. (She was built with a lot of red in mind.)
Baby acts rather mysterious upon her first appearances on the channel. She speaks in a soft, foreboding voice and threatens to take over. After we actually see her crew preparing to do Sister Location custom nights, she seems much more friendly and casual. She seems to be a good leader and cares for her friends.