Sarah, alternately spelled Sara, is Kagetsu's sister and Tiara's childhood friend. A Neutralizer tasked with maintaining the Throne of Yord—the Guardian World's power source—her own abilities remain untapped. Frail and sickly, her delicate constitution is often reflected in nightgown-like attire.

Prior to the main narrative, Sarah mysteriously vanished when she fused with the Throne of Yord, an eldritch abomination. This fusion fulfilled her destiny, preordained from birth. Kagetsu's theft of the Throne to free her ignites the central conflict.

Trapped within the Throne, Sarah's consciousness endures. She reaches out cryptically to Tiara through dreams, offering veiled guidance about the Throne's true nature. The Throne itself exploits Sarah's form, manifesting her likeness to manipulate others, particularly during confrontations with Tiara. This shapeshifting allows it to mirror allies and weaponize emotional bonds.

The climax reveals Sarah and the Throne exist in transdual unity—a single consciousness perceived through divergent perspectives. Within the Throne, Sarah's benevolent aspect surfaces, aiding Tiara and her companions to escape its influence. Her presence enables Tiara to reconcile the Throne's conflicting duality, integrating Sarah's compassionate identity into its power. This act restores balance, permitting the artifact's safe return to the Guardian World.

Sarah's post-fusion existence ascends to a higher plane. She embodies both a mystical waif and an intrinsic component of the Throne's consciousness. Her ultimate fate sees her remain part of the artifact, her kindly personality tempering its power.