My impressions:
Despite being so over the top all the time, it's not losing its charm. Maybe it's even getting better at keeping a straight face while being utterly absurd. Which is why you get a school education that opens with "as part of the first lesson, you will be dying, preferably two or three times each" and you just know this is going to be a wild ride again...
What I love about the series is how the villains aren't the people with the craziest plans, or those who endanger the world around them - that's all par of the course. The villains are consistently the people who think of others as lesser beings, as somebody beneath them, as just tools to be used and not as real people - in short, nazis. And Anos not just defeats them, but also always undoes their plans and helps those they endangered. After all, just because he's overpowered doesn't mean he can't be kind, and vice versa.
There's a lot of plot threads (and threats) going off at the same time in this volume, and a lot of people getting involved. Which is the second thing I love about the series - while Anos is overpowered, he doesn't fight alone, and he doesn't win alone. There's always an opportunity (and space on the pages of the book) for others to have their heroic moments, big or small, to fight and win the battles that are important to them, to sacrifice and learn and give their best and grow. Even the very side characters, like the fangirl union or all the humans in this volume, get to shine.
While Eldmed, the bombastic villain turned equally bombastic teacher, is a delight, the best character around this time is definitely Emilia. She's been appearing in the books from the very start, and has probably changed the most from her first appearance. And I love that it wasn't easy for her - it's not just that she was defeated and proven wrong, but she's struggled with her past and present identity, with her guilt, with the resentment towards Anos, and she's a wonderfully deep character who often manages to be good and bad at the same time. Some of her scenes in this volume made me really tear up, both some of the quiet moments, and the plot where all the side characters are heroes of their own fight.
Favourite moment: Hard to say. Lay and Shin talking things out by fighting with Anos serving as a translator to actual human speech was great, but so was Emilia and Anosh talking over canned food. It's hard to beat Emilia and the students fighting the dragons, though.