In the midst of this clash and din the heavens are rent in twain, and the sons of Muspell come riding through the opening. Surtr rides first, and before him and after him flames burning fire. He has a very good sword, which shines brighter than the sun. As they ride over Bifrost it breaks to pieces, as has before been stated. The sons of Muspel direct their course to the plain which is called Vigrid.... The sons of Muspel have there effulgent bands alone by themselves.
The etymology of "Muspelheim" is uncertain, but may come from Mund-spilli, "world-destroyers," "wreck of the world."