Stashia first appears as a potential guardian shrine maiden for the new Mamamega, expressing reluctance when Lilith, the primary shrine maiden recruiting the team, approaches her. She ultimately accepts the position primarily to protect Rurubell, a younger girl who looks up to her, ensuring Rurubell's safety despite her inexperience.

Physically, Stashia possesses lilac or pale blue hair reaching her hips, blue eyes, stands 171 cm tall, and weighs 51 kg with measurements of 89-60-86. Her preferred color is green.

In combat, Stashia wields a harp that transforms into a bow and arrow, reflecting her graceful and peaceful nature. She fights as a "Musical Assassin," using her weapon to counteract mind control and engage enemies, demonstrated when her attack damages the clothing of the adversary Maharaja. Her elegant and composed fighting style aligns with the "Lady of War" archetype.

Her personality is consistently graceful, peaceful, and cool-headed. She prioritizes protection over aggression, underscored by her decision to become a shrine maiden more to oversee Rurubell's well-being than from personal ambition. This protective relationship defines her mentorship of Rurubell. As a member of the guardian team alongside Lilith, Rurubell, and Juliana, she helps defend their utopian realm against the antagonistic forces led by Yamimama.