>>280145232 (OP)I like it when the villain becomes stronger at the same time as the main character.
I like it when some rather unimportant character or minor villain becomes the main villain in the end. That's why I like the idea of Blackbeard being the final boss in One Piece. A guy you thought was just some random pirate turns out to be Blackbeard the pirate that Ace was searching for. Then he won the fight against Ace and you realize that he will play a much more important role in the story.