This will probably contain spoilers.
I have not read the manga, but am a fan of this anime series and its characters regardless of the various failings both have. However, I was not impressed by S2 and certainly not by this season. It's deviated further from the original idea of a boy-becomes-hero and monster slaying, and I frankly have no clue where it can logically go from here.
The issue with this season is rooted in its premise. In introducing sentient monsters, the creators have attempted to introduce a new level of depth to consider. Yet while the understanding that your enemies are not truly "monsters" is valuable and indeed commendable in reality and realistic media, social commentary in anime is difficult to do well and unpalatable when done poorly. At no time during this anime did the viewer feel truly empathetic to the monster's cause beyond a heavy-handed "look at the monsters suffering now feel bad." Twelve episodes is simply not enough time to properly explore this idea without giving off a feeling of hurried artifice and it is this feeling that detracts the most from enjoying this season.
I will not say that there weren't poignant or memorable moments, especially in the latter half of the season, but as a whole this season did not live up to expectations, and I hope for a return to more of the feel of previous seasons.
