Del

Bel's twin sister. Both thought to be human, but soon discovered of their vampire blood after a certain life-threatening incident that killed both their parents. They are now residing in the dormitory and are seldom seen to attend night classes together.

Del was technically born female, but prefers to stay ambiguous as a non-binary and be called a 'he'*. He is, in front, the protected little sister who seems to be weak and incapable of violence but in all reality, could get more viscious than Bel would ever think he could. While others assume Bel to act as the elder brother, it's actually Del who's more level-headed but is also more childish when it comes to being protective of Bel. Bel is unaware of this and would continue to do so.

Del is usually following Bel in a close distance in just about anything, but would be around the corner whenever the childhood friend, Isaure, is with them. He doesn't necessarily dislike her more like actually relies on her sometimes in the hopes for him to settle with his overprotectiveness. Both of them have always been rather yielding to a personality that is Isaure and that might be because of how she is resembling their deceased mother. 

* Although non-binaries are usually called 'they', Del prefers the gender neutral sense of the usage of 'he' and doesn't mind to be mistaken as a guy.