Kou Nakano is an Ajin. Nakano is very considerate of others;

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stating he wanted to help Kei with taking down Satō, and later helping Kei escape even after he locked him in a wrecked truck.

He was also concerned for Izumi, saying she shouldn't put herself in danger. He is also a bit clumsy compared with other characters and often doesn't know what's going on. As seen in the recent chapters, he is not good with coming up with plans and prefers to improvise instead. This results in him relying on Kei a lot with strategic plans, much to Kei's annoyance. it is revealed that Kō had first died when changing a light bulb. He stacked a bunch of magazines on top of each other, and tripped. After that, he was left paralyzed on the floor for days, but no one came. He then most likely died of dehydration. It is also pointed out that Kō had abusive, or at least neglective, parents.