Walter appears in two different forms during the events of Silent Hill 4: an undead spirit killing 21 victims to resurrect himself, and a young child who believes Henry Townshend's apartment is his mother. In Silent Hill 2's apartment level, there is a newspaper scrap referring to Walter killing his first two victims, twins Billy and Miriam Locane, who later take on the form of a two-headed baby enemy in Silent Hill 4.
Walter was born in room 302 - Henry's apartment - but was soon abandoned by his parents. Frank Sunderland, the father of James Sunderland from Silent Hill 2, finds baby Walter and takes him to the Wish House, an orphanage run by The Order- the religious cult in Silent Hill. While growing up, Walter came to believe that room 302 was his mother. While being at the Wish House, the people in charge made him read about the 21 Sacraments- a special ritual involving human sacrifice made by The Order. As Walter ages, he begins to carry out these Sacraments to "purify" his "mother" starting with number 15 out of the 21.
Cynthia Velasquez - Henry first meets Cynthia in the subway level in Silent Hill 4, and is forced to escort her to safety. After spliting up with her, she is attacked by Walter and stabbed to death. When Henry visits the subway again, she attacks him in the form of a ghost.
Jasper Gein - He was seen at the Forest World where he told Henry he has something that might be useful, but will only hand it over in exchange for something to drink. Once you give him the chocolate milk found in your apartment, he helps you out. Once you get the keys and enter the Wish House, Walter burns Jasper to death. His ghost is found still burning.
Andrew DeSalvo - Andrew is a guard who you meet at the Water Prison in Silent Hill that's run by The Order. Walter drowns him in the basement's generator room. His ghost appears bloated from being drowned, and holds the keys needed to continue the game.
Richard Braintree - Another person living in the same apartment building who was always yelling at the child Walter. He had an argument with another person living in the apartment named Mike, who Richard invited into his room and peeled his skin off. He is electrocuted in his apartment room by Walter. His ghost weilds a golf club as a weapon.
Eileen Galvin - The girl who lives next door to Henry, and is always concerned about him. She is captured by Walter and taken to the Hospital in Silent Hill, where you rescue her and try to escape. She is brainwashed by Walter and goes with him, where you can save her or let her die. Depending on which one you decide on will alter the game's ending.
Henry Townshend - Possibly Walter's 21st victim. Depending on the player's choices, Henry may be killed along with Eileen Galvin.