Ymir, also called Aurgelmir among the giants, was the founder of the race of giants and an important figure in Norse mythology.
Ymir was conceived in the Ginnungagap when the ice of Niflheim met the heat of Muspelheim and melted. From this fusion of primordial Elements was born Ymir Primordial being, unique in kind and nature.
Ymir fed on the four rivers of milk of the primordial cow Auðumbla.
Auðumbla fed by licking salty blocks of ice. From licking the ice came the body of a man named Buri. This was Bor's father, and he and his wife Bestla had three sons, Odin, Vili and Ve.
While Ymir slept, he began to sweat, Under his left armpit grew a man and a woman, and his legs created his six-headed son, Þrúðgelmir.
The sons of Bor sacrificed Ymir, and when he fell, the blood spilled from his wounds drowned the race of giants. Only two giants survived the flood caused by Ymir's blood, these were Ymir's grandson Bergelmir (son of Þrúðgelmir) and his wife. Both founded a new race of giants.
Odin and his brothers used Ymir's body to create Midgard in the center of Ginnungagap. With his flesh the earth was made. With his blood the seas and lakes were formed. With his bones the mountains were erected. From his teeth and bone fragments the stones were made. From his hair grew trees and from his flesh worms formed the race of dwarves. The gods placed his skull on the Ginnungagap and created the sky supported by four dwarves named Norðri, Suðri, Austri and Vestri. These dwarves were given the names East, West, North and South. Odin then created the winds by placing one of Bergelmir's sons in the form of an eagle at the end of the earth. He then threw Ymir's brain into the wind and it became the clouds.
Then the sons of Bor took sparks from the Muspelheim and scattered them across the Ginnungagap, thus creating the stars and the light. With pieces of wood brought back by the sea, the sons of Bor made men. They created a man named Ask and a woman named Embla. With the eyebrows of Ymir, they created a fortress to protect the race of men from the giants.