Demi-ymbrynes are a subspecies of ymbrynes. Like full ymbrynes, they have the ability to reset loops, but they are unable to create new loops or turn into a bird.
Overview[]
Demi-ymbrynes are sometimes paid for their work. Miss Annie calls demi-ymbrynes "functionaries" but some demi-ymbrynes do so out of kindness and love. Exactly how they maintain a loop is unknown.
Norma Abernathy seems to treat demi-ymbrynes and loop-keepers as synonymous, but they are afterwards considered to be different in the series, with Miss Billie stating that only a loop-keeper can wind the clock.