He is a spirit who collides with the Heroine, causing her to lose her memories. Orion is bound to her and can only be separated gradually through the recovery of important memories. He is unable to physically interact with the world or the people in it - including the Heroine, although he has the ability to share a sensory connection with her, allowing him to feel her physical pain and emotional state.

Orion is the servant of the god Lord Nihl; a deity who receives his power by granting the wishes of humans. Because Nihl lent his strength to Ukyo in order to jump across multiple parallel worlds as a way to try and find one in which he and the Heroine both lived, Orion was drawn to the Heroine from the start and is the main reason that he collided with her in the first place.