Walrider is the main villain in the Outlast video game.
Walrider, also known as Billy Hope, is the last antagonist PewDiePie encounters in Outlast. He makes his first appearence on "Outlast Walkthrough Part 2 - PANTS GETS POOPED" on security cameras as he is seen killing the soldiers who were at the asylum before Miles. Also Pewds encounters his appearence on "LOUDER THAN OPERA - Outlast Walkthrough Part 7". After Father Martin was burned to death on a cross, he gave Miles a key to the elevator which will take him to the main exit, but Martin tricked him and the elevator took Miles to the underground of asylum instead. After it,the Walrider finally tries to kill Miles when he tried to escape. When Pewds is running from him, Chris Walker jumped on him and attacks him. When he threw him on the ground, Walrider began to attack him instead Miles, he is filming their attacks and Walrider killed Walker on a vent and he disappeared. After Walker's death, Pewds encounters a patient, he talks about his life with Billy, he takes care of him,considers him as his father and loves him. He wants Miles to kill Billy as Miles can get out of the asylum. Pewds turned off his life support and films his death and Billy tries to kill him. After that, Walrider disappears and Miles falls from the air. When Miles was killed by the soldiers, it is heard the noises and screams from the soldiers, assuming Miles becoming the Walrider.