Chroma is the self-proclaimed evil mastermind of the Fossa Magna, the organization that serves as the antagonistic force to the magical girl Berry Blossom in Niigata City. His full name is Kuroma Kurama, and he is an adult who has held onto a childhood dream of becoming a villainous leader. Despite his grandiose title and aspirations, he is remarkably incompetent in his role, a fact that has led to public disinterest in his battles with Berry Blossom.

Personality-wise, Chroma is a well-intentioned individual who lacks any genuine malice. He loves the aesthetic and idea of sowing chaos but does not carry out any truly evil or harmful actions. His schemes are notoriously weak and often cause only minor inconvenience, such as announcing his intention to sit on a children's park swing and refuse to give it up. Underneath his villainous persona, he possesses a heart of gold and is more of an affable, slightly eccentric adult than a true threat. His inability to be a convincing villain has been described as a form of Peter Pan syndrome, as he refuses to let go of his childhood fantasy. He can become lonely when left alone for too long, and he has a tendency to be overly enthusiastic about his schemes, which often backfire or fail to impress.

Chroma's primary motivation is simply to fulfill his lifelong desire to be a proper supervillain. He finds pleasure in being defeated by Berry Blossom and holds a certain admiration for her, but his ultimate goal is to have exciting, memorable fights that elevate her status as a hero. He is not interested in actually winning or causing real harm; he merely wants to play his part effectively. His role in the story is that of the catalyst. His initial incompetence directly leads the protagonist, Chizuko Date, to become disillusioned with the lackluster battles and eventually agree to become his strategist in order to make Berry Blossom shine brighter.

Chroma’s most significant relationship is with Chizuko Date, whom he recruits and gives the title of "General Dante". He relies heavily on her tactical advice to improve his schemes, and their dynamic is central to the series. He also lives in a secret base located in the crawlspace under the house of Chizuko's grandfather, who ironically is a big fan of Chroma. His backstory reveals a past rivalry with a man named Mashima, who cheated during a competition to join the company Ohmizu Technica. When Mashima was caught, he was transformed into a cat-like creature named Mashirou as punishment. This event indirectly led to the creation of Berry Blossom, as Mashirou sought revenge on Chroma by using a magic card on a kind girl named Kaju Noichigo.

Chroma has a history that explains his current situation. He once competed with his school rival, Mashima, for a position at Ohmizu Technica, the company that acts as a front for Fossa Magna. Chroma won because Mashima cheated and was subsequently transformed into a cat for his transgression. He now works a mundane job at a convenience store to support himself, and his magical abilities are limited by a monthly data plan, often running out at the end of the month. He started his career as a villain before meeting Chizuko, but his early attempts were so pathetic that he considered quitting altogether, a prospect that would have left the city without a magical villain.

In terms of notable abilities, Chroma primarily uses magic to create and control small, seemingly harmless bears, which he deploys as his main method of attack against Berry Blossom. He has possessed this specific ability since childhood, though its origin is unexplained. On rare occasions, these bears can spontaneously combine into a single giant, kaiju-like creature that poses a real threat to the city, a development that horrifies Chroma as he frantically tries to prevent any actual damage. His other magical powers, which are provided by Ohmizu Technica, are more versatile and include the ability to create wormholes or dimensional portals, but his usage is often hampered by his limited monthly allowance.