As the title implies: This is an Isekai anime (An anime where a character gets transported to an unknown world) where a guy gets trapped in his MMO character in a new fantasy world, with his previous NPC companions now gaining full autonomy (while maintaining an incessant undying loyalty to the guy). As a high level player, Ainz Ooal Gown comes to find out that he is in pretty much every sense of the word: invincible in the world that he now calls home.

While the concept was cool for the first season as the main character tries to understand the state of the world, his capabilities and his plan going forward: the series unfortunately suffers from the fatal flaw of making Ainz an omnipotent character. Even through the latest season: there's been essentially no character who's able to come close to the power level of even Ainz' inner circle. This leads to an exposition that relies more on overcoming abstracted political issues rather than some form of tangible villian which may or may not be an issue depending on your point of view. Much of what Ainz' does in order to overcome these tasks is less than savory and makes him seem more like a villian than a protagonist that we should care about too.

In short: while not necessarily a bad series: I feel like much of the potential was wasted in this one. If you're looking for an Isekai, I'd recommend Re:Zero instead.