Fenrir (or Fenris) was a gigantic and terrible monster in the shape of a wolf, the eldest child of Loki and the giantess Angrboda. The gods learned of a prophecy which stated that the wolf and his family would one day be responsible for the destruction of the world. However, rather than kill Fenrir, the gods kept him in Asgard, due to being Loki's son. Only the god of war, Tyr, dared to feed and take care of the wolf.
When he was still a pup they had nothing to fear, but when the gods saw one day how he had grown, they decided to render him harmless. However, none of the gods had enough courage to face the gigantic wolf. Instead, they tried to trick him. They said the wolf was weak and could never break free when he was chained. Fenrir accepted the challenge and let the gods chain him with a special fetter, Loding. Unfortunately, he was so immensely strong that he managed to break Loding as if it were cobwebs. They tried again with another chain, Dromi, which had double the strength of Loding, but again the wolf easily snapped it to pieces.
After that, the gods saw only one alternative left: a magic chain. They ordered the dwarves to make something so strong that it could hold the wolf. The result was a soft, thin ribbon: Gleipnir. It was incredibly strong, despite what its size and appearance might suggest. The ribbon was fashioned of six strange elements: the footstep of a cat; the roots of a mountain; a woman's beard; the breath of fishes; the sinews of a bear; and a bird's spittle.
The gods tried to trick the wolf a third time, luring Fenrir to the underworld with a promise of sheep to eat, only this time Fenrir was less eager to show his strength. He saw how thin the chain was, and said that was no pride in breaking such a weak chain. Eventually, though, he agreed, thinking that otherwise his strength and courage would be doubted. Suspecting treachery however, he in turn asked the gods for a token of good will: one of them had to put a hand between his jaws. The gods were not overly eager to do this, knowing what they could expect. Finally, only Tyr agreed, and the gods chained the wolf with Gleipnir. No matter how hard Fenrir struggled, he could not break free from this thin ribbon. In revenge, he bit off Tyr's hand.
Being very pleased with themselves, the gods carried Fenrir off and chained him to a rock (called Gioll) a mile down into the earth. They put a sword between his jaws to prevent him from biting. On the day of Ragnarok, Fenrir will break his chains and join the giants in their battle against the gods. He will seek out Odin and devour him. Vidar, Odin's son, will avenge his father by killing the wolf.
About the star
Epsilon Ursae Majoris (ε UMa, ε Ursae Majoris) is the brightest star in the constellation Ursa Major (despite its Bayer designation being merely "epsilon"), and at magnitude 1.76 is the thirty-first brightest star in the sky. It has the traditional name Alioth (from the Arabic word alyat—fat tail of a sheep).
It is known as 北斗五 (the Fifth Star of the Northern Dipper) or 玉衡 (the Star of Jade Sighting-tube) in Chinese.
It is the star in the tail of the bear closest to its body, and thus the star in the handle of the Big Dipper closest to the bowl. It is also a member of the large and diffuse Ursa Major moving group. Historically, the star was frequently used in celestial navigation in the maritime trade, because it is listed as one of the 57 navigational stars