Usamaro

Usamaro behaves much like a very young child. He is curious, playful, affectionate, and quickly becomes attached to Rin after being treated with kindness. He enjoys food, games, and companionship and responds enthusiastically when Rin includes him in ordinary activities.

His defining motivation is a sincere desire for people to be happy. The problem is that Usamaro initially understands happiness in extremely simple terms: painful memories make people sad, so removing those memories appears to him to be an act of kindness. He does not naturally understand that grief, regret, responsibility, and unpleasant experiences can also be necessary parts of a person's identity.

Usamaro is therefore dangerous without being malicious. Unlike demons who knowingly exploit human suffering, he can cause enormous harm while believing that he is helping. This makes Rin unusually sympathetic toward him, because Rin recognizes that demonic power does not automatically determine moral character.

He is also highly sensitive to abandonment. His ancient history is shaped by the experience of being loved by human villagers and then rejected after his attempts to remove their sadness caused them to neglect their responsibilities. That betrayal leaves him desperate to preserve happiness whenever he finds it again.

Usamaro possesses an unusual ability to consume memories. He primarily removes painful or unpleasant memories, after which affected people forget the events and responsibilities associated with them. The power is broad enough to affect numerous people throughout True Cross Academy Town rather than functioning only through direct physical contact.

The removed memories are connected to the mist surrounding his rabbit-like tail. Because his victims do not remember what has been taken, the ability can be especially difficult to identify until inconsistencies in their behavior accumulate.

Usamaro's power extends beyond memory. He can also "eat" time, effectively removing a period of events from the normal flow of the world. This ability is vastly greater in scale than his ordinary memory manipulation and places tremendous strain on him.

He is not primarily a physical fighter. His danger comes from altering cognition and causality rather than attacking opponents directly, making him fundamentally different from the combat-oriented demons Rin usually encounters.

Usamaro appears during preparations for a festival held once every eleven years in True Cross Academy Town. Rin, Yukio Okumura, and Shiemi Moriyama are sent to deal with the Phantom Train, and a small demon escapes during the mission. Rin later encounters the child and names him Usamaro. The official film site lists him among the movie's principal original characters.

The True Cross Order initially considers exorcising him, but Rin objects and is permitted to supervise him instead. Usamaro becomes part of Rin's everyday life, eating and playing with his new companions while the festival preparations continue.

Usamaro is eventually revealed to be connected to an old legend about a demon who once lived alongside human villagers. Wanting to make them happy, he removed their unpleasant memories; without those memories, the villagers forgot work, obligations, and eventually the practical responsibilities required for their community to survive. An Exorcist ultimately sealed him away.

The same pattern begins repeating in the present. Usamaro removes the Exorcists' unpleasant memories so that they can enjoy the festival, causing them to forget duties required to maintain the town's defenses. Demon activity consequently spreads throughout the city. Rin realizes what Usamaro has done and teaches him that painful memories have value because they shape people alongside happy ones.

When the consequences threaten to overwhelm the town, Usamaro uses his greater power to consume the disastrous interval of time itself, undoing the catastrophe at enormous personal cost. The rewritten outcome causes almost everyone to forget him, while Rin retains enough of their bond to continue remembering the demon boy and the promise between them. The film's plot centers on Rin helping Usamaro understand the value of memories rather than simply destroying him.

Rin Okumura is Usamaro's closest companion. Rin gives him his name, argues against immediately exorcising him, and takes responsibility for caring for him. Their relationship resembles that of an older brother and younger child, with Rin attempting to teach Usamaro ordinary behavior while also defending him from people who see only a demon.

Yukio Okumura is more cautious about Usamaro than Rin. His professional experience makes him less willing to assume that a seemingly harmless demon is actually harmless, and his suspicions ultimately prove important once Usamaro's abilities begin affecting the town.

Shiemi Moriyama treats Usamaro kindly and spends time with him alongside Rin. She is among the first people to notice evidence that memories are disappearing when events Usamaro has erased no longer match what she remembers.

Shiro Fujimoto never meets Usamaro during the movie's present-day events, but his influence reaches the relationship indirectly. A story Shiro once told Rin and Yukio about a demon who erased painful memories turns out to describe Usamaro's past, giving Rin the information needed to understand what the child demon truly is.

Cheng-Long Liu is an Exorcist involved in the festival security operation and has knowledge connected to the demon's historical sealing. He regards Usamaro as a threat that may need to be eliminated, placing him in conflict with Rin's insistence that the demon can understand his mistakes rather than simply be destroyed.