Final answer:
In The Prose Edda, Fenrir is imprisoned by the Aesir using a magical ribbon called Gleipnir after they were unable to contain him with regular chains. The ribbon was crafted from mystical elements, making it unbreakable. Tyr loses his hand in the process but secures Fenrir's bondage until Ragnarok.
Step-by-step explanation:
How is Fenrir Imprisoned by the Aesir in The Prose Edda:
The tale of Fenrir, a fearsome wolf in Norse mythology, is recounted in The Prose Edda, a collection of Norse myths compiled by the Icelandic scholar Snorri Sturluson. In the story, the gods of the Aesir foresee that Fenrir will cause great harm and decide to imprison him. Initially, they attempt to bind him with strong chains, but Fenrir breaks free with ease. Seeing no other way, the Aesir resort to a magical ribbon called Gleipnir. Crafted by dwarfs from items such as the sound of a cat's footsteps and a woman's beard, it appears harmless but is incredibly strong.
They trick Fenrir into letting them put Gleipnir on him by playing it off as a game to test his strength. To gain his trust, the god Tyr places his hand in Fenrir's mouth as a pledge that they will release him if he cannot break free. When Fenrir realizes he cannot escape, he bites off Tyr's hand. The ribbon holds, and Fenrir is securely bound until the events of Ragnarok, during which he is prophesied to break free and partake in the end of the world. The imprisonment of Fenrir exhibits the fear and respect the Aesir held for his power, and their actions reflect the complexities of fate and free will in Norse mythology.