C-21 is a unique being, born of a secret union between human and Majin. In her human form, she appears like a young, athletic woman with gentle features and clear, light-blue eyes. She seemingly lives a normal life, wears loose clothing, and exudes a friendly, curious aura. But beneath this facade lies immense power.

Her Majin form reveals a completely different side: shimmering violet skin, bright pink eyes, wilder hair, and a magical aura that noticeably transforms any environment. In this state, C-21 is more playful, impulsive, and tends to use her powers without much restraint.

The transformation occurs when strong emotions are triggered—anger, euphoria, danger—or when she wants to impress herself or someone else. She can also change at will to optimally utilize her abilities. Despite the power of her Majin form, C-21 feels that both sides are equally important: Her humanity keeps her grounded, while her Majin side gives her strength.

C-21 lives between two worlds, searching for her place—torn between calm and chaos, heart and power. Every encounter with her could be a journey to both extremes.