"It's so hot," the maiden murmured, seemingly activating a rune. The mythril spear in her hand dissolved, reforming into a shape closer to its original form—a large harp. This silver instrument, with its elegant curves reminiscent of a winged swan, was a gift from her half-goddess mother, Brynhildr.
It was said to be an external wing granting the user freedom to soar through the skies. Unlike levitation or flight achieved through magical energy or runes, becoming one with the winged harp granted the maiden the ability to reach supersonic speeds and pierce the stratosphere. Her body and wings became one as she rode the wind, breaking the sound barrier in a single breath to put distance between them and the attackers.
Shielded within the magical wind, Ragnar clung desperately to a part of the wing, barely managing a strained reply, "Whoaaaa... This is no easy ride!"

Fate/Lost Einherjar, Chapter 3