The Cute Fairy is the divine servant of Kumiromi of Harvest, one of the deities of Elona. Cute fairies have the special ability to spit out seeds when they eat, making them a boon for farming players.
Like many characters in Elona, "cute fairy" is merely a "class" of characters, and has a randomly generated name given to them upon spawning into the world. (For example, "Finola the cute fairy".)
The cute fairy by default has green hair, a white dress, yellow hair ribbon, fairy wings, and is quite small... except when you notice that their in-game stats say they're actually human-sized, because their size is race-based, and all servants have the Servant race template.
In spite of their appearance, cute fairies can be either male or female. In Elona+, cute fairies have gender-based evolutions to either the (female) Dryas (presumably, a corruption of "dryad"), or the (male) Deathscythe.