Arthur One

Arthur is composed, professional, and strongly committed to Yamato Mori's mission. The destruction of his original homeland gives his protection of Yamato a personal dimension: he has already experienced what happens when a country fails to survive catastrophe.

He behaves like an experienced senior Keeper rather than an impulsive frontline fighter. His abilities are among Yamato Mori's best, but he uses them pragmatically for defense, crowd control, investigation, and large-scale combat rather than relying solely on destructive force.

As the Sand Choujin, Arthur can freely create and manipulate sand. He can shape it into weapons such as firearms, construct defensive barriers, and produce enormous quantities at once. Create: Sand Tsunami releases enough sand to overwhelm large groups of opponents.

Sandulate allows Arthur to transform materials directly into sand. Objects produced through another Choujin's ability resist this conversion, making the technique useful for distinguishing ordinary matter from Choujin-created material.

Arthur can also transform his own body into sand, allowing attacks to pass through or disperse portions of him rather than inflicting conventional injuries. He possesses Raise in addition to these abilities.

Arthur enters the story among the experienced Yamato Mori personnel mobilized as the organization prepares for increasingly large confrontations. His rank and strength place him alongside the senior Keepers entrusted with protecting Yamato from threats beyond what younger operatives can handle.

During the Tower of Mourning operation, Arthur fights as part of Yamato Mori's force against Sora and her followers. His large-scale sand manipulation makes him particularly useful against numerous enemies and within the Tower's chaotic battlefield.

Later, Arthur's Sandulate helps Yamato Mori investigate the mysterious aircraft used in attacks on Yamato. His inability to convert a recovered section reveals that the aircraft itself was produced through Choujin power, providing important evidence about the nature of the new enemy.

Hoshi Sandek is one of Arthur's fellow senior figures within Yamato Mori and shares responsibility for defending the prefecture.

Ichirou Satou works with Arthur as part of Yamato Mori's leadership and strategic structure.

Tokio Kurohara serves in the same organization and participates in major operations alongside Arthur.

Sora Siruha becomes an enemy of the Yamato Mori force in which Arthur fights during the Tower of Mourning operation.