Oskar von Horrificus- is the main protagonist of the original series. He is a student in the Academy for Vampires and is the Count's nephew. Oskar tries to be a great student, but he is unable to for his main problem that conflicts him throughout his days in the school, his fear of blood.
Oskar transfers to the school for vampires sometime before the beginning of the series, but it is likely his parents sent him to stay with the Count to improve his vampire behavior with his fear of blood. Other than his phobia, Oskar has a crush on a mortal girl named Sunshine Polidori who doesn't know Oskar is a vampire and it makes it worse that Paulus Polidori, her grandfather is a vampire hunter who lives next door to the school.
Oskar is really in love with Sunshine and she seems to love him back. However, he seems to be unaware that his friend, Gruftine Gothettiticus has a crush on him, despite obviously being jealous when Oskar spends time with Sunshine. She was also once annoyed with him for being with her while they had to write an essay together for class.
At some point before the series, Oskar had also one point met Sunshine and spends a lot of evenings with her and mentions that he lives far away from her home, instead of being a vampire student.
In one fan interpretation, sometime in the future after graduation, Sunshine and Oskar are married, Oskar turns Sunshine into a vampire and they have a daughter together, Moonshine von Horrificus.
In a different fanfiction, "School For Little Vampires, Plus One" by Therecameaspider, Oskar becomes friends with a new student named Holly. Holly's mother is a vampire named Morgana, whom supposedly attended school with Count Von Horrificus and Klaus Pumpkinfiend when they were all children. Holly's father was a mortal man. It is implied in the storytelling that Holly has been aging like a vampire, despite not actually being one. Oskar, along with Gothetta, are both kind to Holly and seem to welcome her readily despite her taboo half-heritage. It is uncertain if Oskar will have any personal thoughts on what Holly is, since he is likely still with Sunshine in SFLVPO's setting. When Stoker Flestcher plays a prank on Holly that gets her into trouble, Oksar tells Gothetta that he has a plan to get back at Stoker for his bullying. He never gets to act upon it as the castle is attacked by Polidori that same evening. After Count von Horrificus confronts Polidori and the vampire hunter is chased off, Oskar admits his plan was to have Stoker brag about what he had done to Holly.
Count Alerich von Horrificus (uncle)
Inga von Horrificus (mother)
Oskar's father (father)
Moonshine von Horrificus (future daughter)