K100D — The helper turns out to be a prince, ATU 314.

At the end of the story, the animal helper (horse, lion, etc.) turns into a prince (princess) itself.

Berezkin category: Adventures: Acts of heroes

This is of motif type Adventures and tricks and is part of group 10, Adventures.

K10.  A monstrous bird (bat) attacks people, heroes engage in battle with it. See motifs K10A – K10G.
K10a.  Heroes kill a dangerous bird; during or before the battle, they hide in a shelter (hut, cage, vessel, sack, well) or cover themselves with an object that protects the body.
K10b.  A huge bird carries away to its nest a cage, bag or other container in which people are located. See motif 10A.
K10c.  The hero (twins) is weighed down with the blood-filled intestines of an animal. A bird pierces them with its claw, blood flows, the bird thinks its prey is dead, and brings the man to its nest. He kills the adult bird and either kills or transforms the chicks. Cf. motif M91A.
K10d.  A flying monster carries the hero away to a distant island. The hero kills the monster and uses a boat, bridge or rope made from part of the monster's body to return.
K10e.  In the bird's habitat, the hero finds the people it has kidnapped and helps them return home.
K10f.  The character turns the children of a flying monster into ordinary eagles or owls.
K10g.  Finding himself in the nest of a giant bird on a tree or rock, a man descends to the ground with the help of an adult bird (attaching its feathers or wings to himself), and more often - a chick (grabbing its legs, sitting on the chick, attaching its feathers or wings).
K10h.  A bird carries a woman or boy to its nest, feeds them, but does not let them go. The captive runs away.
K10i.  The tree opens its trunk and hides the hero fleeing from a man-eating bird. The monster that flies in after him is held tightly by the tree, which squeezes its trunk again.

This motif has been recorded in 26 traditions: Ireland, England, British, Bretons, Scotland, Scots, Picts, Scotti, Scottish, Portuguese, Portugal, Maltese, Sicily, Sicilians, France, Germans: North (Low- and Central German dialects): Schleswig-Holstein, Mecklenburg, Pommern, Niedersachsen (Lower Saxony, incl East Frisia and Oldenburg), Nordrhein-Westfalen, Hessen, Rheinland-Pfalz, Thüringen, Saxony-Anhalt, Sachsen, Brandenburg, Rügen, Kashubians, Slovakians, Slovaks, Latvians, Estonians, Finns, Karelians, Vepsians, Western Sami, Eastern Sami (including Skolts), Norwegians, Swedes, Danes, Danish, Lkungen (Straits; including Samish, Songish, Sooke, Lummi), Klallam, Galicians, Icelanders, Italians: Central (Toscana, Umbria, Marche, Lazio), Lutsi (Ludza), Russian Federation