Demonic posession, or extreme gaming addiction. The Koreans know it well.
"South Korea has a significant issue with gaming addiction, particularly among adolescents, which has led to government interventions and a focus on treatment and prevention. The high prevalence of gaming culture, coupled with strong internet infrastructure, has contributed to this problem. Treatment centers, school programs, and even laws like the "Shutdown Law" (also known as the "Cinderella Law") have been implemented to address the issue"