Ren Iruga (入賀煉), a 17-year-old male standing at 175.2 cm with a lean 61 kg frame and blood type O, bears striking yellow-blond hair and golden eyes. Born May 21 under Gemini, his turbulent past originates in a detention facility, where he forged a reputation as a cunning troublemaker.

Bound by loyalty to his best friend Teppei, Ren initially allied with Midou in Part 1, driven by a nihilistic crusade to eradicate humanity—himself included. Teppei’s dying plea reshaped his path, spurring him to join forces with Saneatsu in upholding justice and entrusting him with critical sealed orders. Post-emperor’s demise, Ren vanquished Midou before vanishing without trace.

In Part 2, he operates covertly with Yagibashi and Sudō to destabilize the queen’s regime, infiltrating her inner circle while masking his agenda. His detention facility trauma, stemming from Ouga Shihouten’s brutal privilege-acquisition experiments, haunts him psychologically, crippling his combat efficacy whenever Ouga resurfaces.

Ren wields the "Division Right," enabling him to nullify assaults by splitting targets—though limitations apply—and an ambiguously defined "Tracking Right." A tactician at core, he thrives on manipulating information gaps to control outcomes. His psyche oscillates between nihilistic despair and fractured idealism, transitioning from apocalyptic ambitions to clandestine rebellion. Institutional abuse and loss have etched deep fissures in his psyche, fueling internal clashes between self-preservation, ideological extremes, and the scars of his traumatic history.