It turns out that mcs coworker had a crush on him and then the incident happened where mc transported. After that the coworker started trying to figure out what had happen to him and where he went. After years of research he found out where mc went and then went there himself, only to find out that he transported 300 years earlier than the day mc did. So when he realized that, he was full of regret and anger that yin over took his body and he became the Demon King. he then created a bunch of clones and yan San was just a clone that the demon king had sent to go looking for mc. At the end the clone has completed his mission so he disappears/dies and tells mc to find the coworker and save him.
WHAT????? NOOO!!! WHAT THE FUCK NOOOOO
can someone explain to me what’s going on