Spica Virgo (Female): The protagonist of Black Cat and the Witch's Classroom. Although her skills are lacking, she works hard to become a 1st-class Archmage and has the potential to grow stronger as the story progresses. Due to magic traits determined by her birth constellation, she can basically use plant manipulation magic. Uniquely, she possesses Regeneration Magic that does not belong to the 12 systems, giving her faster recovery than others and making her the only one who can break the Curse of Samsara placed on Claude. Claude Sirius (Male): Spica's master. A 1st-class mage. He was the first in history to be appointed as a professor at Diana at the age of 17, contributing to the cultivation of the next generation of mages. It is rumored that he fled without protecting his students when cultists attacked Diana, but he actually protected Spica from them when she was young. During the confrontation, he was hit by the Curse of Samsara and turned into a cat. The only way to lift the curse is Spica's 'Regeneration Magic,' but because the gap between Spica and Claude's skill is so large, the curse cannot be fully broken unless Spica becomes a 1st-class mage. He returns to Diana after two years and becomes the homeroom teacher for the class including Spica. He was reinstated thanks to his master-disciple relationship with Jeanne, the principal of Diana, but he is disliked by students due to his two-year disappearance. To clear his name, Jeanne gives him a trial: he must take charge of 12 students with strong 'individualities' in his class and ensure every single one graduates without being expelled. If he fails, he must leave Diana. Aria Aquarius (Female): Spica's childhood friend who entered the school with her and belongs to the same class under Claude. Her constellation is Aquarius, and she uses water magic. She is a true frenemy to Spica, often teasing her while she's focused on magic training or making bets when Spica asks for help, eventually treating Spica like a maid for a day when she loses. However, contrary to appearances, she has trauma regarding her dreams. Io Taurus (Female): In the same class as Spica. She attended the middle school division at Diana. Her constellation is Taurus, and she uses gigantification magic, but because she is so strong, she reportedly causes frequent property damage accidents. Astrea Libra (Male): The son of the vice-principal of Diana Magic School. His constellation is Libra, and he can perceive his surroundings with magic even with his eyes closed. He is a huge womanizer. Leo Regulus (Female): Her constellation is Leo, and she fights by possessing her body with various beasts, including lions. She seems to enjoy standing out. Unlike other characters, her name is 'Leo,' which signifies her constellation. Capella Capricorn (Female): Her protective constellation is Capricorn. An eccentric who aspires to be a delinquent. She is appointed as the class leader by Claude. The name 'Capella' is uniquely the alpha star of the constellation Auriga. Yu Aries (Female): Her constellation is Aries. Due to her natural laziness, she becomes the academy's top sleeper shortly after entering. She awakens during a training camp and begins to engage in magic training in earnest after a life-threatening experience. Mellow Pisces (Female): Her constellation is Pisces. As the daughter of a fisherman raised by the sea, she specializes in marine magic. She has an optimistic and somewhat eccentric, '4D' personality. Chiron Sagittarius Aradia (Male): His constellation is Sagittarius. He looks like nothing more than an arrogant and cocky brat, but he is actually the second prince of the Kingdom of Aradia! The name 'Chiron' comes from Cheiron, the protagonist of the Sagittarius constellation in Greek mythology. While his overall aptitude for magic is the lowest, he honed his control and played an active role in the boss battle after the training camp. It seems a flag was raised with Spica during this process. Hana Sasorijo (Female): As her surname suggests, she is blessed by Scorpio and boasts top-tier skills in poison magic. However, the image of such magic is not very good, and since her control is not yet proficient, she has become an object of avoidance among students due to cases where even fellow students were caught in it. Jeanne Orion (Female): The principal of the Royal Diana Magic School. Claude's master. Despite being much older than Claude or the students, she has a youthful appearance. Justice Libra (Male): The vice-principal of the Royal Diana Magic School. Astrea Libra's father. According to Claude, he is terrifying when angry. Arcturus (Female): She appears as a girl with pink-gold twin-tails and uses magic to summon snakes to kidnap Spica. She used to possess magic, but now Spica holds the Regeneration Magic.