Rei is an avatar roaming the digital ecosystem forged after Skyfall, the catastrophic collision of a fallen orbital colony with Earth. His core task is harvesting scattered "seeds" within the impact crater, though his grasp of the mission's wider context remains limited. During this duty, he encounters the enigmatic Mil (Mildred), whose nature—human or kaiju—is ambiguous. This meeting forms a central pillar of his documented existence. Rei maintains a connection to an operator in the real world, yet specifics of this link or his origins remain unexplored. His actions unfold against themes of life's fairness and human-kaiju coexistence in a world without national borders. No significant character development, expanded background, or appearances in other official media are detailed.