So why did Aramun want (Eunseom)him dead when he was a baby (ep1) and in episode 2 the horse rider alluded that…
I think Aramun want to possess Eunseom, not to kill him. The white snake in the first episode might be Aramun trying to possess him. So for now, Eunseom is Aramun. This is just what I think :) btw you should mark this as spoiler