A young-looking girl who was given the Sacred Task of operating an elevating disk between the 50th and 80th floors of the Central Cathedral in Underworld, with no other instructions to follow. To be able to make continued use of her services, Quinella had the natural degeneration of her «Life» frozen, enabling her to work continuously for 107 years, only being allowed to rest for lunch and during the night.
She was likely granted a large System Control Authority and skilled at using Sacred Arts, as she is able to generate 10 elements in one chant, which is a rather difficult feat to achieve.

Her name was revealed in Volume 19.

(Source: Sword Art Online Wikia)