Sylph
Encyclopedia Entry:
A wind elemental born from concentrated “wind elements” joined with the “monster’s demonic energy.” They’ve become monsters with a woman’s form. They are capricious and free-spirited monsters like the wind. Ordinarily they hide themselves and fly around the sky with the wind, so they can be quiet difficult to find; however, often times they descend and reveal themselves on a whim.
They form a covenant with a man through the act of sexual intercourse. They men who form a covenant with an elemental in this way are called “elementalists.” It is said that they become able to make use of the sylph’s “power of wind.” Even after the forming of a covenant, they always fly around near their covenanter, suddenly dropping in out of nowhere, unexpectedly kissing, hugging, and fawning on him, likely driving him crazy with their characteristic capriciousness and lack of inhibition.
Wind elementals had a strong interest in the romance and sex of men and women to begin with, so when they find a man they like, they seek intercourse and a covenant almost the same way a child begs to be played with. Even after forming a covenant, they remain very curious about sex, which drives them to peek and watch the couplings of other monsters. They’re likely to try the same things with their covenanter soon after. Through having intercourse with them in this way, the covenanter is able to receive the power of wind necessary to use the power through their bodies. In doing so, the sylph is able to get spirit energy from their covenanter, and their elemental power, and the power of wind usable by the covenanter grow proportionately more potent.