He married Gudrun (Kriemhild), the sister of that king, and won for him by a stratagem the hand of the Valkyrie Brynhildr, with whom he had himself previously exchanged vows of love.
According to the German story they were killed at the instigation of Kriemhild in revenge for Siegfried.
In the north, indeed, the name Grimhildr continued to have a purely mythical character and to be applied only to daemonic beings; but in Germany, the original home of the Nibelungen myth, it certainly lost all trace of this significance, and in the Nibelungenlied Kriemhild is no more than a beautiful princess, the daughter of King Dancrat and Queen Uote, and sister of the Burgundian kings Gunther, Giselher and Gernot, the masters of the Nibelungen hoard.
As she appears in the Nibelungen legend, however, Kriemhild would seem to have an historical origin, as the wife of Attila, king of the Huns, as well as sister of the Nibelung kings.
In the Nibelungenlied, however, the primitive supremacy of the blood-tie has given place to the more modern idea of the supremacy of the passion of love, and Kriemhild marries Attila (Etzel) in order to compass the death of her brothers, in revenge for the murder of Siegfried.