Casa Clubs is a member of the Crown Knights, the quartet of heroes who protect the Card Kingdom. Often known by her full designation of Casa Clover XVII, she serves as the team's mystic. Her primary function is to act as the group's sensory specialist, possessing psychic powers that allow her to sense anything in her surroundings. Her fine-tuned senses are described as being so sharp that she could hear an insect sneeze from a mile away. This perceptiveness establishes her as the member of the team most attuned to danger and the environment.

In terms of personality and combat style, Casa Clubs is characterized as the group's combat expert and its designated badass. She is a martial artist who relies on her physical prowess and superhuman senses in a fight, setting her apart from teammates who rely more directly on speed or magic. Her notable ability is a powerful martial arts technique called the Sonic Boom, which is also referred to as the Sonic Bomber. This attack represents the peak of her physical combat abilities and is her primary offensive contribution to the team.

Within the story of the two-episode OVA, Casa Clubs and the other Crown Knights are called into action when the Card Kingdom is invaded by giant, sentient chess piece-shaped combat machines. Her role is to stand on the front lines of this conflict, using her combat skills and psychic senses to fight the invaders and defend her home. Information regarding her personal background, individual motivations beyond protecting the kingdom, and specific character development throughout the series is not available. Her key relationships are defined by her membership in the Crown Knights, working alongside her teammates Jo Diamonds, Coco Heartful, and Sunday Spade.