Kako Tengan is a prominent lawyer celebrated for her widespread media presence and professional achievements. She features plum-colored hair extending to her buttocks and striking violet eyes, consistently adorned in refined attire: gold earrings, a red necklace, a cerulean top layered over an off-blue shirt, a navy blue skirt, and matching shoes. Her public facade radiates calmness and maturity, yet beneath this veneer lies a divergent personality marked by promiscuity, selfishness, irascibility, and immaturity.

She harbors an intense fascination with mahjong, driving her to organize the competitive "Libertas-Cup" tournament. During this event, she encounters Yōta Narukami, an amateur participant whose unconventional playing style captivates her. Impressed and allured by his approach, she declares him the tournament victor. Subsequently, she extends an immoral proposition to him, which he declines. His rejection triggers a visible behavioral shift, unmasking a previously concealed arrogance and volatility.

Her interactions unfold chiefly within the mahjong tournament narrative, where she serves as both organizer and catalyst for Yōta's involvement, facilitated by Hina Sato's guidance.