Chanyeol's a medical student, proudly class of '61. He hasn't questioned where the cadavers come from until a classmate asks him to ride along on a pick-up, in the middle of the night, at the cemetery.

Chanyeol finds a weird book in the library. He tries to read the weird book. At the time, he didn't know it was a spellbook that would divide his soul and give the bad half a physical manifestation and allow it to roam free. Live and learn.

A body and its reflection always match. They have to.

Chanyeol just wanted to be a Good Samaritan. Not all good deeds pay off.