Mariana commands Kurobara Communications, a shadowy entity specializing in orchestrated kidnappings and psychological manipulation. Known as "Black Rose," she lures targets through calculated gambits, such as deploying Marie Whitebear as sacrificial bait. Her signature thorned whip serves as both weapon and symbol of her unrelenting control. She fixates on the protagonist, Penguin, whose eventual revelation as Mariana’s biological daughter complicates her ruthless agenda.

Her operations rely on Aqua, a tactician wielding precision card-based assaults, and Reef, a bumbling yet loyal assistant whose frequent errors test Mariana’s patience. Though driven by strategic cruelty, her hidden maternal ties to Penguin introduce layers of conflict, blurring lines between malice and twisted familial loyalty. Interactions emphasize her relentless pursuit of dominance, framed by unresolved tensions between her role as antagonist and mother.