Rembart Saiki, also known as Rembart Psyche, is the close friend and colleague of Phoron Tatara. Their bond formed during studies at Torvas Divine Song Players Academy, where Rembart excelled as a talented honors student. Both later joined the Office Tsuge Divine Song Players Management Group.

As a Dantist, Rembart performs Divine Songs using a saxophone-like instrument. He operates without a contract to a major spirit, uniquely collaborating instead with minor spirits: the small, two-winged fairies Bōrai and Jimutīru. These spirits frequently accompany him, assisting in tasks and demonstrating his expertise in managing lesser spiritual entities without formal pacts.

Beyond his musical and spiritual skills, Rembart possesses considerable practical ability in cooking. His role within Office Tsuge involves supporting missions and operations, often working alongside Phoron and other team members. This includes diverse tasks, such as participating in searches for missing entities like a lost cat.

Rembart appears in multiple franchise iterations, including the original Crimson visual novel series, its anime adaptation, and related light novels. His character remains consistent as a reliable and skilled Dantist, defined by his instrument proficiency and reliance on minor fairy spirits rather than a contracted spirit partner.