Satou stops being a villain and starts being right, which breaks the entire moral framework the show built in season one. Kei has to fight someone he can't actually defeat, not because the guy is stronger, but because the guy has a point. The CG is rough enough that some viewers bail, but everyone who stays watches a show about three factions of immortals with genuinely incompatible demands, and no faction gets to be the heroes.
Kei Nagai has stopped running, but his choice to stand and fight arrives at the worst possible moment. Satou, a fellow Ajin who refuses to be silenced, unleashes a calculated campaign of violence against the government. Disgusted by years of hidden torture inflicted on captured Ajins, Satou demands accountability through bloodshed. His target list grows longer each day, and the bodies pile up as he executes those responsible for the experiments. Kei realizes he cannot face this threat alone. Learning to harness the supernatural abilities that mark him as inhuman, he seeks out other Ajins, people society fears and rejects. Building an unlikely alliance becomes his only path to stopping Satou before the terrorist's rampage consumes everything around him. The line between hunter and hunted blurs as immortal beings clash. Trust becomes dangerous when everyone involved can survive death, and ideology proves more lethal than any weapon. Kei discovers that stopping a madman who cannot die requires becoming something he never wanted to be.