Itsuki Otomo served as a military pilot in the 15th Integrated Task Force of the Japanese Ground Defence Force. He operated within a close-knit unit that included Teppei Sugo, who provided aerial support, and Rin Otomo, the ground commander and his wife. The unit was deployed overseas for Operation: Foot Stamp, an intervention to assist in a revolution. Itsuki was reported killed in action during this operation. The official account attributed his death to a nerve gas deployment—a biological weapon tested by the Japanese military against the enemy, which also eliminated the rest of the strike team. The military concealed the true circumstances of the operation and Itsuki's fate, declaring the land forces missing in action to obscure the testing of the experimental weapon. Some time later, a combat drone using a holographic projection of Itsuki Otomo’s appearance carried out a series of terrorist attacks against Japanese military leaders. This prompted an investigation by the MWPSB, during which Teppei Sugo was suspected of aiding his supposedly alive friend. The investigation uncovered that the drone was an android implanted with Itsuki’s memories after his death, created as an instrument of vengeance for the betrayal and cover-up. The exposure of the military’s actions, along with Rin Otomo’s own attempt to assassinate those responsible, profoundly affected Sugo. The psychological strain contributed to his deteriorating mental state and later decision to join the MWPSB as an Enforcer.