Characters who are vastly overpowered seem to me to be more of a fantasy thing compared to other genres. More specifically, I'm talking about wizards and other magic users. These are the people in fantasy literature that can seemingly defeat armies on their own and move mountains by just using the power of their minds. While this is undeniably cool, it also makes it hard to relate to them as characters or become invested in their stories. To give you a good example, there is Milamber or "Pug of Crydee" as he was initially known from the Riftwar books by Raymond E. Feist. Here we have a character who basically starts out as an orphan that was abandoned by the side of the road and ended up becoming an apprentice to a great magician. I don't want to venture into any spoilers, but Milamber goes on to accomplish incredible feats of magic that makes him far more powerful than any of the other characters in the books. It also causes the author to resort to the laziest of overpowered character cliches by making his loved ones his weakness. Meaning that because his enemies are not really able to harm him, they kill those close to Milamber, which in my opinion is a cheap way of milking emotion from readers for a character that is too overpowered. The author generally does a good job of not shying away from killing important characters, which keeps readers on their toes, but Milamber is never in any real danger of dying.