The protagonist is surely an important character. His inner world forms the core of the story, so understanding his personality, motives and growth is key.
Another theme could be the struggle with one's own psyche. In the light novel, the character may face various internal challenges that are symbolized as 'dangers'. For example, dealing with insecurities, fears or unacknowledged desires. It's like a battle within the heart.
My Fox Fairy Girlfriend is an anime that is similar to the Demon Envoy of Zero. There are many animes that are recommended below:
1. Steins;Gate
2. Attack on Titan
3 Sword Art Online
4. Tokyo Ghoul
5 Demon Slayer
A Certain Magical Index
7. A Certain Scientific Railgun
"Even a chuunibyou needs to fall in love!" (One Piece)
Date a Live
10 Puella Magi Madoka Magica
The above are some recommendations that I hope can help.
The character development is often a great aspect. In animes like 'My Love Story', we see the characters grow and change as they experience love. They learn about themselves and their partners, which makes the story engaging.
One anime like 'My Love Story' could be 'Toradora!'. It also focuses on a love story between two high school students who initially seem mismatched but gradually develop deep feelings for each other. Another is 'Kaguya - sama: Love is War'. It has a similar theme of the back - and - forth in a relationship, with the two main characters being too proud to admit their feelings at first. And 'Lovely Complex' is also a great choice. It's about a tall girl and a short boy falling in love, much like the unique pairing in 'My Love Story'.