Henry Miller is a person who was mentioned lots of times in DSAF 2.
He is a person that killed kids in Frebear's Family Diner. He killed Phone Guy's human form, who tried to stop him, as well as the kids he lured. He also laughed when Old Sport was dying in the suit he was stuffed in. He was the mentor of Dave.Dave even says,that Henry was way more chaotic,evil and psychotic than Dave himself. He died in 1983, possibly either to the animatronics intentionally killing him, or during an unconfirmed event known as the Bite of 83. Dave got his fake name by using his surname Davy Jones, and his last name Miller.
In the books, he is the father of the protagonist, Charlie, and commited suicide after her friend Michael got killed by Dave. He used to own Freddy Fazbear's Pizza.