Ochiai, a scientist and former member of the Immortal Ship Committee—Sidonia’s clandestine governing body—orchestrated catastrophic experiments over a century before the main timeline, seeking to fuse human and Gauna biology into a Chimera. This endeavor nearly annihilated Sidonia, resulting in his arrest, the obliteration of his physical form, and the preservation of his consciousness within a neural interface. His legacy fractured into three entities: the imprisoned original mind, a rogue nematode-based agent, and a memory-less cloned body employed by Captain Kobayashi to interface with his sealed intellect. Driven by a fixation on transcending humanity’s biological constraints, the original Ochiai reemerged during the series through a Gauna hybrid form, dubbing himself Chimera Ochiai. This evolution symbolized his life’s work merging immortality research with interspecies hybridization, positioning him as a self-proclaimed mediator between humanity and the Gauna. Sidonia’s crew, however, perceived his metamorphosis as a perilous gambit. In *Love Woven in the Stars*, he escalated his ambitions, attempting to fuse his consciousness with a Gauna hive mind to attain eternal existence. Framing this act as a bid to end the war through unification, he hijacked Sidonia’s systems and weaponized Gauna replication, only to be defeated by Nagate Tanikaze in a final confrontation. Ochiai’s experiments birthed hybrids like Tsumugi and Kanata, engineered from Gauna placenta and human DNA, cementing his posthumous influence on Sidonia’s biotechnological evolution. His research advanced their comprehension of Gauna physiology, yet his ethical transgressions and obsession with immortality overshadow his contributions. A recurring force in Sidonia’s conflicts, Ochiai epitomizes the clash between unchecked scientific ambition and moral accountability. Through his preserved consciousness, clones, and creations, his ideologies persistently shape the colony’s strategies for survival, probing the limits of humanity and the dangers of manipulating Gauna biology.