The Ymir was the name given to a a cruel and bloodthirsty nation of humans hungering for domination that originally created the machines to instigate a cruel and unnecessary war against other nations to take over the planet, with their original name long-lost in cyberspace. Originally, the YMIR were the foremost leading nation on the earth before the start of the machine war which originally created the complex humanoid machines to fight their war of domination versus the other nations. After the defeat of the nation of YMIR, the children of the YMIR, the machines, continued to fight the war against humanity, creating a never ending winter of war when antimatter weapons used during the war cause an artificial global snow storm.
From examination of Jörmungand and Mimir's notes that the YMIR were more technologically advanced then the Aesir. When Thor comments on building an Aesir version of Jörmungand, Mimir retorts that the technology to even manufacture the armored shell of the vessel lies well beyond the abilities of the Aesir. Whether this due to loss of industrial capacity or due to loss of knowledge is not clarified, but it is apparent that the Ymir were a highly advanced nation despite their barbaric tendencies. In addition they were responsible for other great feats of military engineering with the Devastator Class war machines, being their best example. Originally dozens were constructed. Jörmungand is the last known surviving example, however it is hinted that other such warships may still be hidden. It is revealed by Loki that the machines also mine data from cyberspace wells, but they are only dimly aware of the data's significance. It is also noted that their programming is not optimized for free thought. Tyr notes that the machine's programming also allows them only iterative improvements of models, which has kept the machines from simply "out-evolving" humanity.
In Norse mythology, Ymir is the primordial giant and the progenitor of the race of frost giants. He was created when the ice of Niflheim came in contact with the hot air from Muspell and melted, releasing "eliwaves" and drops of eitr. The eitr drops stuck together and formed a giant of rime frost between the two worlds and the sparks from Muspelheim gave him life. While Ymir slept, he fell into a sweat and conceived the first race of giants. One of his legs fathered his six-headed son Þrúðgelmir on his other leg while from under his left armpit a man and women grew out.
The frost kept melting and from the drops the divine cow Audumla was created. From her udder flowed four rivers of milk, on which Ymir fed. The cow itself got nourishment by licking hoar frost and salt from the ice. On the evening on the first day her licking the rime ice revealed the hair of a man, on the second day the whole head and on the third day it became a man, Buri, the first god. Buri fathered Borr, and Borr and his wife Bestla had three sons: Odin, Ve and Vili.
Odin and his brothers had no liking for Ymir, nor for the growing number of giants, and killed him. In the huge amount of blood that flowed from Ymir's wounds all the giants drowned. Only two giants survived the flood of Ymir's blood, one was Ymir's grandson Bergelmir (son of Þrúðgelmir), and the other his wife. Bergelmir and his wife brought forth new families of giants.
From the slain body the brothers created Midgard, the earth at the center of Ginnungagap. They used his flesh to create the earth; his blood to create the lakes and the seas; from his unbroken bones they made the mountains; the giant's teeth and the fragments of his shattered bones became rocks and boulders and stones; trees were made from his hair. The maggots which swarmed in Ymir's flesh they gave wits and the shape of men, but they live under the hills and mountains. They are called dwarfs. Odin and his brothers raised Ymir's skull and made the sky from it and beneath its four corners they placed a dwarf. These dwarfs were given the names East, West, North and South. Odin then created winds by placing one of Bergelmir's sons, in the form of an eagle, at the ends of the earth. He cast Ymir's brains into the wind to become the clouds.
Next, the sons of Borr took sparks from Muspelheim and dispersed them throughout Ginnungagap, thus creating stars and light for Heaven and Earth. From pieces of driftwood trees the sons of Borr made men. They made a man named Ask-ash tree and a woman named Embla-elm tree. On the eyebrows of Ymir the sons of Borr built a stronghold, named Midgard, to protect the race of men from the giants.