[Liked trope] The character we first meet and that serves as our introduction to the story isn't the protagonist but antagonist.

in Goh manhwa the first person we meet is Mujin Park who in the end becomes the main antagonist. I love this introduction. It shows us what Mujin is about when he crushes the entire island because a guy who is a bit problematic is there. This introduction also foreshadows later events a bit.

in Hero has Returned(manhwa) the first person we meet is Kim Minsu. We see how miserable his life was since he returned to our world after saving another. it's easy to assume that he is the MC of this story. that is until he decides to kill everyone who dares to be happier than him.