Takeichi stands as a loyal companion to the protagonist within a dystopian society fractured into the polluted, impoverished "Outside" and the privileged "Inside." A member of an outlaw biker gang, he navigates the lawless margins with mechanical limbs—makeshift substitutes for the advanced medical nanotechnology reserved for the wealthy. These prosthetics embody his marginalization, temporary fixes until he can secure proper treatment.

Guided by mentor Masao Horiki, he joins raids into the "Inside," striking at symbols of oppression. During one mission, he delivers a neurotoxin payload targeting the S.H.E.L.L. network, the system controlling public health and immortality, cementing his defiance against systemic control.

His bond with the protagonist is defined by repeatedly salvaging him from self-destruction—overdoses, suicide attempts—forging a cycle of dependency and guardianship. This dynamic fractures during a violent clash: transformed into a monstrous "Lost," the protagonist spirals into chaos, crushing Takeichi in the turmoil. His death becomes the catalyst for the protagonist’s reckoning with identity and systemic corruption.

Though his personal history remains unspoken, Takeichi’s mechanical augments and insurgent actions visually anchor themes of resistance against class disparity. His elimination shifts the narrative’s axis, thrusting the protagonist into confrontations with power structures and the cost of rebellion.