Cuz of kihoon's bad luck????
Literally what bad luck. ._. He got into a car accident and just got scared of taking risks.
Kihoon is a blazing red soul (ppl w no bound fate) those who ties a red thread on blazing red souls ( yeon tied a red thread to kihoon in their past life) will cause bad luck in them, it was mentioned. Try reading again, cuz I also questioned kihoons bad luck.
To undo what yeon did, they have to restart
Literally what was the point of yanking us through the other parts of the story if it was going to end exactly where it started?