A fairy tasked with helping out the protagonist of a tale, whether it's granting wishes, or other things. Why this is so is almost never said, although some stories will have an organization of them. This is also a highly Discredited Trope these days, usually associated with the most archaic parts of Fairy Tales, even though this trope is a lot more recent than most of those stories. A Sub-Trope of Our Fairies are Different. Compare Fairy Companion, God Was My Copilot.
Hello, Unknown Troper. You'll need to get known to lend a hand here.