Years before he becomes the man hunting Kei Nagai, Special Forces operative Satou, callsign 'Fox,' helps his unit take an African warlord alive, then opens fire out of boredom the moment the job is done and is knocked out by a fellow soldier as he moves to execute the captive. The stunt costs him a dishonorable discharge. Not long after, unknown attackers gun him down and he gets back up unharmed, realizing he is an Ajin, the same kind of immortal near-human his unit had brought in alive in Africa. This OVA fills in Satou's origin as a supporting release alongside the main Ajin series.