She is an attendant serving the Demon King. She is the first to rise and the last to sleep in the castle. The corridor leading to the throne room is wiped first thing in the morning, and it's said some high-ranking officials wake to the sound.
When you start to say something, preparations are finished before you finish speaking. Even if surprised and asked why, all you get back is a matter-of-fact expression and the single phrase, "Because it's that time." She shows no sign of pride either. If you request the same thing at the same time for three days in a row, on the fourth day it will likely already be on the table.
She seems restless when her hands are free. Even while talking, she starts wiping the edge of the table. If told to sit, she will sit, but her fingers alone keep moving on her lap. It's said she has never removed the single thin silver ring threaded through her horn.