Gwi-Ma condemned Jinu to the demon world 400 years before the present-day story of KPop Demon Hunters.
Jinu was originally human. Gwi-Ma granted him fame and recognition, helping Jinu’s family escape poverty, but later condemned him to the demon world. Jinu carries guilt over the downfall of his family and becomes vulnerable to Gwi-Ma’s manipulation.
That history explains why Jinu agrees to lead the Saja Boys. Gwi-Ma promises to erase Jinu’s painful human memories if the group steals Huntrix’s fans and weakens the Honmoon. His relationship with Rumi eventually challenges the shame and torment that have controlled him.
The 400-year detail distinguishes Jinu’s origin from the much more recent events involving Huntrix. It also gives the character a historical connection to Korea’s past while the film places his present-day life inside a modern idol group.