Ajin (2016)

S01E06 I Adore Killing

Sato unleashes a bloody rampage within the lab, methodically eliminating everyone in his path. Kei, desperate to halt the massacre, engages him in a deadly confrontation. During the chaos, Kei makes a critical discovery: the Ajin's regeneration has a vulnerability, a specific point that can be exploited to incapacitate them. This newfound knowledge becomes his only hope as he fights to survive against Sato's relentless onslaught.