I quite enjoyed the first three seasons of Overlord, once I got around to watching them,
Based off the light novel by Kugane Maruyama, Overlord follows the story of Sataru Suzuki (Satoshi Hino), a salaryman who, while playing a video game, was isekaied into a fantasy world, along with various other NPCs loyal to his character, Ainz Ooal Gown.
Seasons One through Three followed Ainz’s journey to learn about the new world around him, while his NPCs misinterpreted this as an attempt to take over the world, practically steam-rolling every culture they came across due to being so overpowered.
Season Three saw Ainz’s conquest of the Re-estize Kingdom begin in bloody fashion and this follows through to become the main plotline of Season Four, with the CGI being being much more digestible than it was in that third season, where it was pretty terrible
The first and third act of this season are also great, with the first few episodes wrapping up storylines in the Baharuth Empire in humorous fashion, while also setting up the dark third act by introducing the colossal idiot known as Philip (Yoshitsugu Matsuoka).

It is the second act of the season where things falter a bit, though, as the Dwarf storyline did feel pretty rushed to me compared to the other ones.
Along with this, there were two whole volumes cut from the anime after the Dwarf arc, so there was a bit of confusion surrounding some events in the third act.
However, we will still be getting an adaptation of the cut volumes in a movie, so we have that to look forward to.
As for the third act, it does a great job of bringing the season together, especially with how it handles its characters.
Ainz continues to both be funny and cruel, Pandora’s Actor (Mamoru Miyano) finally gets more screen time, and the other Floor Guardians also have their moments.
It is the side characters I was most impressed with this season, however; specifically Renner (Kiyono Yasuno), Zanac (Kouji Fujiyoshi) and Brain (Koji Yusa).

Renner continues to be the entertaining psychopathic yandere that she is, with her manipulations being fun to watch play out.
Brain has a great standout moment in the last few episodes.
As for Zanac, he really surprised me with his heroism this season.
When we were introduced to him in Season Two, I expected to hate him but, much like Ainz, I had a newfound respect for him after this season.

Coming back to Ainz and the Floor Guardians, if viewers somehow did not get we were following the villains after the third season, they should definitely realise it now.
As I mentioned in my review for the first few seasons, Ainz and his crew are so overpowered that all we can do is hope that the heroic characters can survive their genocidal actions and, sometimes, they do not.
At least there is plenty of humor to provide levity for following such evil characters.
And if there’s one thing we can always count on Overlord for, its providing a good OP.
Season Four’s, “Hollow Hunger” by OxT, is another excellent one that I never skipped throughout.

Overall, Season Four is a pretty good one for Overlord.
The quality of animation is much better than Season Three, the beginning and ending of the season are great, and side characters like Renner, Zanac and Brain really shine.
Now, I am just curious about where the anime goes from here?
Maybe we will get an idea when the movie finally releases?
I have heard from Light Novel readers that the volumes the movie will adapt are some of the best in the entire series so that it exciting.