Ryōka Yūki, class representative for Kei and Midori's class, hails from the wealthy Yuuki Group family. She maintains a polished poise but openly clashes with Midori and especially Miki Sawanaga, driven by a fiercely competitive streak. Her affluent background defines her, yet her family faces inevitable financial ruin leading to bankruptcy in every story route, forcing her to transfer schools.

Physically, Ryōka possesses long, wavy blond hair, amber eyes, and stands 157 cm tall. She is typically seen in her school uniform vest and skirt. Her personality embodies the tsundere archetype, presenting outward arrogance masking inner shyness. Despite her initial distance, she develops genuine romantic feelings for Kei Ogata.

In the OVA, her role diminishes, though she retains her class representative position and hostility towards Midori and Miki. After the main events, she maintains email contact with Kei. During this time, her parents join a fringe religious group, and her mother takes work at a love hotel. There, her mother witnesses Kei engaging in an affair and reports this incident to Ryōka.

Her character receives limited exploration across official media, with her narrative primarily shaped by her family's downfall and unreciprocated affection for Kei. Post-story details focus on her family's ongoing decline rather than her personal resolution or growth.