Daimajo Marba is a witch who resides in the Demon Realm and plays a pivotal role in the lore established by Dragon Ball Daima. She is elderly in appearance, possessing a large, corpulent body with lavender-colored skin and distinct demonic features, including black eyes, two pointed horns, and a pair of large wings on her back. She typically wears a black robe that leaves only her face visible, complemented by red sleeves with a serpentine pattern. A large insignia of the demonic "M" symbol is displayed on her chest, and she wears a large bone necklace centered with a green jewel. A notable physical trait is her apparent lack of legs, as she is always seen floating, presumably through the use of her magic.

Marba is a talented and powerful witch whose primary ability is the unique magical expertise required to create artificial genies. This knowledge is so rare that even accomplished wizards and scientists like Bibidi and Dr. Arinsu cannot achieve it on their own. It is revealed that she was the original creator of Majin Buu, having been commissioned to do so long ago by the wizard Bibidi. She keeps this fact a secret because Buu's uncontrollable and destructive nature caused immense chaos, leading her to regret the consequences of her own creation. In addition to Majin Buu, she is also connected to the Saibamen, as she once possessed a large number of their seeds and sold them to outsiders, explaining how these creatures arrived in the outside universe.

In terms of her personality, Marba is not inherently loyal to any particular individual or cause. Instead, she operates with a pragmatic and somewhat amoral disposition, willing to collaborate with those of evil or ambitious intent, provided she is sufficiently rewarded for her services. This trait is central to her role in the story of Dragon Ball Daima, where she is approached by the scientist Dr. Arinsu. Arinsu seeks to exploit Marba’s skills to create a new, controllable Majin. Using a fragment of the original Majin Buu that Arinsu had secretly collected, Marba agrees to the plan. Her motivations are not driven by grand ambition but by a transactional nature; she performs her magic in exchange for compensation, living a reclusive life in a small house on a floating island in the First Demon World, far from other creatures.

Her role in the narrative is that of a crucial facilitator and creator. She is responsible for the birth of new characters who become central to the conflict. Her first new creation, Majin Kuu, is made by combining a Saibaman seed with the extract of Majin Buu. When Kuu proves to be weaker than anticipated, she later creates a second being, Majin Duu, at Arinsu's request. Her actions directly drive the plot forward by providing Dr. Arinsu with powerful new assets and altering the balance of power in the Demon Realm. Beyond her specialty in demon creation, Marba has demonstrated other magical talents, including telekinesis for moving objects and the ability to fly or levitate. Her existence serves to recontextualize the origins of major elements from the original Dragon Ball series, establishing her as an ancient and highly significant figure within the Demon Realm's history.