Cassim is a male student attending the Rosewood Academy, the central setting where heroes are trained. He is depicted as an adolescent with brown eyes and brown hair cut to neck-length, and he is often seen wearing gloves and boots as part of his attire.

In terms of his role at the academy, Cassim is considered to be a member of the lower class of students. His fighting style specializes in the use of knives, indicating a proficiency with bladed weaponry that likely requires precision and agility rather than brute force. His personality, as observed in his interactions with peers, suggests a pragmatic or perhaps cautious nature, particularly when faced with situations that involve emotional conflict. During a training exercise within a virtual reality world, Cassim and a fellow student, Clay, found themselves overwhelmed after being defeated by a group of female students, leading them to retreat. This event highlighted a key aspect of his character, where the emotional dynamics between male and female combatants became a point of contention; the boys considered the conflict to be a form of roughhousing, while the girls interpreted the same actions as bullying.

The motivations driving Cassim are primarily tied to his training and survival within the academy environment. The incident that caused him to run away was not solely about physical defeat but stemmed from a misunderstanding over the nature of the fight itself. His development within the story appears linked to overcoming such interpersonal hurdles and regaining his motivation to battle effectively alongside his classmates. While his specific relationships are not detailed, his primary social interactions are shown to be with his fellow lower-class students, including Claire, Yessica, and particularly Clay, as they are frequently grouped together in training scenarios and share similar struggles.