a spirit that lives in the forest : wood nymph, fairy
for the greek all of nature was instinct with life… every tree had its dryad, and the oak was sacred to zeus, the olive to athene, the bay to apollo, the myrtle to aphrodite, the poplar to heracles.
— world religions
… a sunrise stroll with a dryad in a dew-drenched forest …
— edith wharton
the mood (or tone) of the prologue is considered as sombre, dark, since from the start we're being told that this story is going to be a story of love, death and loss.