Ryuna holds the position of priestess at Etwarl Temple, a recurring role within the Shining series. She appears as a playable character in Shining Tears and features in Shining Wind, Shining Wind X, and the anime adaptation. Her physical appearance includes gray eyes (officially noted as blue) and gray hair (officially described as black), typically worn waist-length. Her attire consists of a distinctive hat, detached sleeves, a dress, and boots, consistent with her priestess duties.

A former member of the mercenary knighthood Weissritter, Ryuna maintains fierce loyalty to its founder, Zero, even after his isolation from humanity. She accompanies him in the Astral World alongside the dragon warrior Lazarus, serving as one of his few companions. Her magical expertise lies in healing, light-based spells, and support magic, marking her as a powerful sorceress.

Ryuna wields the Soul Blade "Seiryuuken Amanomurakumo" (Holy Dragon Sword Heavenly Cloud Bush), a weapon emitting bright light that banishes undead and demonic entities while hindering their movements. Following Souma Akizuki's inheritance of Zero's mission to protect End Earth, Ryuna transitions to traveling with Souma's group. She joins Lazarus, Elwyn, and Blanc Neige as part of his core team dedicated to ending the war and preventing the awakening of Zeroboros.

She demonstrates profound trust in Souma, willing to risk her life for him. This loyalty and adaptability are evident as she shifts allegiance from Zero to supporting Souma's leadership within Weissritter. Her journey reflects a commitment to mediation and peace, aligning with the group's goal to resolve conflicts nonviolently across End Earth.