Dryad

Encyclopedia Entry:
A tree-dwelling variety of spirit. Dryads can live as long as the trees they are bound to, but if the tree withers the dryad’s life will end. Though usually gentle, they will mercilessly attack anyone who damages the forest. Extremely enthusiastic lovers, dryads lure in desirable men and trap them within their trees. Men who remain imprisoned in a dryad’s tree for a long time will begin to physically merge with the tree. A man thus affected will share the dryad’s long life, unable to die until the tree withers, and unable to escape the dryad’s endless passionate love.

Normally, dryads are sustained by nutrients from the earth and photosynthesis. When a dryad has sex with a captured man, however, the tree produces an extremely nutritious sap that is the staple food for married dryads and their husbands. The more a dryad feeds on this sap, the more energetic she becomes and the larger the tree grows. Because larger trees also produce more sap, the tree of a married dryad can grow to tremendous sizes.