Overpowered

The "isekai" genre is typically defined at the bare minimum by someone being sent to another world with different rules, but more commonly defined as a human being from Earth (usually Japan) being sent over to an abstractly "fantasy" world. It also typically grants the isekai'd protagonist "cheat" abilities that are "overpowered" so readers can live out a power fantasy. But what even is that?

Note: Some of these aren't actually isekai, but isekai is the most prominent type of series to have "overpowered" stuff. There is also "I can't believe it's not isekai", where the only real difference is that the overpowered guy is NOT from another world. This typically doesn't matter much.

The first type of "overpowered" I see is the most brutish kind. It is simply taking what is there and turning the numbers WAY up. This is what the most bottom of the barrel trash uses. The guy is super good at the thing, so he can kill monsters with a sneeze and women fawn over his might. This is vastly uncreative on its own. Like, sure, it feels good to be able to run headfirst into a problem, but what remains after that? The best series with this premise answer this question in fascinating ways. One Punch Man answers this question by saying "good question". Saitama is on top of the world, and it blows. He can only empathize with the alien conqueror who comes to Earth spoiling for a real battle, and even then, Saitama holds back specifically because he can empathize. Another title that answers this question is the verbose and unwieldy "I Was Reincarnated as the 7th Prince so I Can Take My Time Perfecting My Magical Ability". Lloyd answers the question of what to do on top of the world by looking for even greater peaks to climb. This small child begins pushing the limits of what is possible with his new level of raw might, and isn't interested in anything else but snagging as much power as he can. Surprisingly enough, this series is NOT a complete power fantasy. Lloyd can solve a whole number of problems by simply doing magic about it, but there are problems that he can't hit with a blast, because he's not quick enough. This series also shows how bizarre Lloyd's fascination with magic actually is. He would rather be hit by a spell designed to murder him in less than a second just to know how it works and do it himself. He's a really weird kid.

The next type of "overpowered" I see takes a little more thought. The protagonist has an ability that changes the game (literally and/or metaphorically). This varies far more wildly in terms of series quality. I actually want to divide this into two subtypes based on the categorization of whether anyone else can do what the protagonist can do.

For some series, protagonists start out with a beginner advantage in the form of being difficult to plan around. When Aang pops out of the iceberg in ATLA, no one has fought an airbender for one hundred years. Very few living people still remember how airbenders even fight. Thus, on top of Aang's natural gifts with airbending, he also gets to exploit the fact that no one has any clue how to handle him. There's no defined point at which Aang's homefield advantage goes away, but I do think it does diminish as the series goes on, with Aang's other three elements kind of filling in the gaps. Another