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

In Volume 19, the Elevating Operator's name is said to be Airy

(Source: Sword Art Online Wikia)