First, let's go over the positive points:

The world-building is excellent; you can tell the author put a lot of thought into the backstory. That's a big plus for me.

This novel has some really high points. For example, the scene with Tristan and his father is incredible, as is his fight with Blanche.

Tristan's backstory is well-written, and I also like his relationship with Helga.

The bad:

Now, I'd say my biggest issue with this novel is the characters—specifically, Tristan. At first, I liked the idea that he wouldn't change his personality too quickly, but literally, after just a few chapters, the MC was already a completely different person, and no one questioned it.

No one even mentioned the fact that his family had made a deal with a demon and that he supposedly couldn't use magic, yet the MC could. And again, no one questioned it.

The heroines are quite one-dimensional, honestly. Bella seemed interesting at first since she was his ex-fiancée, and I liked her perspective, but she simply fell into the cliché of "save the heroine, and she falls for the MC." I'm not saying that's bad—many novels use this—but the problem here is that it feels too simplistic and inconsistent. Maybe the MTL affected how I perceived it, making it seem this way. There's also the issue with Wendy, who is 12 years old, while the MC is 20.