Dryas

A high level mid class spirit specialized in earth spirit arts whose principal body it's the enormous world tree located near the spirit folk's village, since they settled there more than one thousand years ago the spirit people has deified, held annually in her honor the spirit festival, hidden her main body from the rest of the world with several layers of barriers and attended to her, in exchange she gives her blessing to the village's inhabitants when they reach a certain age, something that raises slightly their total quantity of magic power and their aptitude for spirit arts and lets them to use the world tree's sap as an ingredient for the spirit liquor, elixirs and panaceas.

(Source: Seirei Gensouki Wiki)