i think they mentioned him in the last chapter. if so he's one of the guys at the beginning of the story that was with MC's parents when they went out to the area that was about to get flooded by the incoming morning tide.
last chapter hinted at the possibility that he may have purposefully convinced MC's parents to go out to the area knowing they would likely be killed. MC asked ppl to look for the guy.

Who is this park daeson again?