Great premise and huge potential for a great story that quickly turns into garbage writing and kids show.
It had a good base recipe for an interesting story:
A good,hardworking, likeable adventurer who, despite all of his effort, cannot move past the limitations of his body. gets killed and finds himself to become a monster while retaining seemingly intact consciousness, personality, and memories. All while having a mad scolar/mage/love interest who is willing to hide and help him stay human on the inside.
It had no isekai BS, no harem. No stupid, silly jokes, and good art to boot.
It explores the themes of : The meaning of humanity, Struggle with his growing monster urges, Getting stronger, and overcoming the limitations of his human past self, Exploring fantasy world full of guilds, dungeons, monsters, kingdoms etc.
I watched up to ep 4 after which I went to read the Light Novel since usually it is better and provides more details and a better story since anime adaptations tend to change things to fit the anime format. So I know the full story in advance.
After episode 4, the quality takes a nosedive, and it only gets worse from there. Remember the premise and all the major themes the show explores in the beginning? When you can forget it.
The show becomes extremely silly.
All the mature content gets removed. And by mature, I do not just mean blood, death, or sex.
I mean anything that an adult can enjoy. Complex and engaging story with twists and interesting and realistic human behavior. Good writing in general.
All the philosophical, moral, and dark parts just cease to exist. The author will mention them but will never actually show them.
The story becomes a collection of filler episodes and scenes that push the same things over and over without showing us any new perspective on things or character development of any kind.
The number of silly and stupid things in the later part is insane. It completely abandons the initial themes and turns into the adventures of your friendly neighbor, Spider-Man, I mean, vampire adventurer. Every Saturday at 10 a.m. at Fox Kids!