The anime is not over yet, there are three more episodes coming out near the end of December

I felt oppostie to this, the first half felt like a slog (；′⌒') but I really enjoyed the end of the season (❁´◡'❁)

It's not that good, but better and more interesting than expected. Roots of a good story are there but it was poorly executed in my opinion

I think he is acting like a child, and the show even acknowledges this! It is stated by the demon king that his appearance takes on the reflection of the one he's talking to, and when he converses with Bashbarza, the Demon King looks like a kid