Yuna Band

The Yuna Band is the group responsible for the rumors that surround Yuna about being cursed. They've caused accidents to befall those who get close to her, in order to isolate her from others. The group was likely founded after the murder of Ji-Hyun Park, which most of the current members unknowingly collaborated with in some way. Bustard often gave compensation in cash to the members of the Yuna Band in return for doing favors to him.

At one point, Woodpecker has a monologue about the truth behind Yuna that likely stems from their otaku behavior. She says that Yuna will be the key to salvation when the Earth reaches the brink of its destruction. Without knowing this, Yuna lives a fairly normal school life, although isolated by her peers. It's been said that she is in constant danger from those who wish for the planet's destruction. The Yuna Band was constructed for the protection of Yuna and the world.

This is not actually the case.

Bustard
Seemingly the leader of the group, Bustard is the one giving orders and is feared by the other members.

Cuckoo
Known as Cuckoo within the Yuna Band chat group, his real name is Jun-Hoo Kang. He goes to a different school than the one Woodpecker and Parrot go to and s roommates with Crow. He was in the Yuna Band chat before the other members were, which signaled to some connection between him and Bustard, who was the leader.

Woodpecker
The collective identity of Sunah and Sunmi within the band. It's not clear which of them is from which reality and whether one is more involved in the group's messaging than the other.

Parrot
Shung

Crow
Rin