Death of Ymir

Summary

In the beginning, there was Muspelheim the land of fire, Niflheim the land of ice and between them lie Ginnungagap the gaping abyss.
The icy winds of Niflheim and spitting flames from Muspelheim grew and grew until they finally met in Ginnungagap. Amid the chaos, fire melted the ice and the water drops fell to form Ymir. As they slept the mighty Jotunn began to spring from his legs and the sweat of his armpits.
Fire continued to melt ice birthing a great cow Audhumla who provided nourishment to Ymir while she fed upon salt-licks in the ice. Her licks uncovered the first of the Aesir which led to Odin, God of Knowledge and Allfather.
After a time, Odin, God of Knowledge and Allfather led his brothers in slaying Ymir. The Aesir began using his corpse to form the realms. His blood made the oceans, his skin and muscles made soil, his hair bore vegetation, his brains clouds, and his skull the sky.

Variations & Mutation

As a culture with very little in the way of written history or myth, most stories are preserved orally or artistically. So key things tend to stay the same but the details often shift.