ENTERING THE COMA
Yaesol is first seen outside of the school by Youngho. She eyes Youngho down, most likely because he might have some connection with what's happening with their school, including Taehoon's death. When Youngho first talks to her, she basically tells him to "get lost". It is assumed not long after Youngho ends up in The Coma, she enters too.
She explores what she calls the Shadow Realm in search of what's most likely a certain "Shade". As she keeps a lookout, she eventually has a run in with Youngho at the Cafeteria of the school. Impressed that he made it this far, he answers a few of his questions such as where he is and that the world is dangerous. She even explains that this creature that looks like Ms. Song (Youngho's teacher) that has been chasing Youngho with a razor blade; isn't the real Ms. Song. She is just a puppet of sorts being controlled by something called a "shade". Youngho doesn't seem to believe her and wishes to return to his own reality.