Fenrir was killed in Ragnarok, the Twilight of the Gods.
According to one version of the myth, Fenrir will devour the sun, and in the Ragnarök he will fight against the chief god Odin and swallow him. Odin's son Vidar will avenge his father, stabbing the wolf to the heart according to one account and tearing his jaws asunder according to another.
Prose Edda
In chapter 51, High foretells that, during Ragnarök, the wolf Fenrir will devour Odin, and Víðarr will avenge him by stepping down with one foot on the lower jaw of the monster, grabbing his upper jaw in one hand and tearing his mouth apart, killing him.
At Ragnarok, the wolf would break loose and join the giants and other monsters in all-out war with the gods. Fenrir would kill Odin by swallowing him. Odin's son Vidar would then come forward and step with one foot on the wolf's lower jaw.
With the forces assembled there, an immense battle will take place. During this, Odin will ride to fight Fenrisúlfr. During the battle, Fenrisúlfr will eventually swallow Odin, killing him, and Odin's son Víðarr will move forward and kick one foot into the lower jaw of the wolf.
So Fenrir asked that one of them put his hand into his mouth. Knowing that if Fenrir was left unfettered, he would have grown strong enough to kill all the God's and destroy the world. Tyr was the only one who had the courage. When Fenrir sensed he had been tricked, he bit off Tyr's hand.
He roamed freely about Asgard, frightening the goddesses. He scared even Odin, for Odin knew that in the Last Battle, it was his destiny to be destroyed by Fenris.
Superhuman Strength: Fenris is monstrously strong, strong enough to lift hundreds of tons with ease. It has proven stronger than even the mighty Thor himself, and with time and patience it will grow to even larger proportions further increasing its already immeasurable strength and durability.
As many of us might know, Odin and Fenrir were the sworn enemies in Norse mythology. The prophecy had it that in the days of Ragnarok, Fenrir would swallow Odin destroying the glory of Norse Pantheon.
Odin has pretty clearly been shown to be demonstrable more powerful than the other gods. Odin's Odinforce has far outstripped anything Zeus's magical lightning bolts have ever done.
Surviving gods
Hoenir, Magni, Modi, Njord, Vidar, Vali, and the daughter of Sol are all stated to survive Ragnarok. All of the remaining Æsir then reunite at Ithavllir. Baldr and Hod return from the underworld - Baldr having been killed by Hod, and Hod by Vali, before Ragnarok.
Conclusion. Until now, there is no agreement about who is the most powerful son of Odin. Because each of them had each distinctive power. If we put all of them in an order of time, we can see that Thor presented the past, Vidar was the present and Baldur was the future.
Odin's son Vidar will avenge his father, stabbing the wolf to the heart according to one account and tearing his jaws asunder according to another. Fenrir figures prominently in Norwegian and Icelandic poetry of the 10th and 11th centuries, and the poets speak apprehensively of the day…
Odin (Old Norse: Óðinn) is the most powerful and wisest god. Odin is the Allfather of the Norse gods and the ruler of Asgard. Thor (Old Norse: Þórr, Thórr) is Odin's youngest son and the second most powerful god.
Garm is found in Helheim by Atreus and Thrúd while they were searching for the last piece of Odin's mask. Seeing that the giant wolf was in chains, Atreus wanted to free him, but Thrúd tried in vain to persuade him not to, as she correctly believed the beast was in those chains for a good reason.
In Norse mythology, Sköll will catch up to the sun the day that Ragnarök begins. This idea caused plenty of panic to arise in the event of a solar eclipse, which were taken as a sign that Sköll had caught up to the sun and Ragnarök was on its way.
Loki – Thor's archenemy and adoptive brother. The son of Laufey, ruler of the Frost Giants of Jotunheim, one of the "Nine Worlds" of the Asgardian cosmology. He is a master of spellcasting and trickery.
They're both really bad but Zeus had the excuse of being corrupted and was under the influence of Pandora's box which made him act the way he did while Odin was always selfish and manipulative on his own naturally.
1 GALACTUS
Barring the Celestials, of whom Thor has only had the displeasure of encountering less than a handful of times, his greatest cosmic adversary is Galactus.
Vidar is sometimes known as the Norse god of vengeance. Through the literature of Norse mythology, Vidar was called “the silent As,” “possessor of the iron shoe,” and “slayer of Fenrir.”
Vidar is a figure in Norse mythology, described as the silent god and almost as mighty as Thor.
In chapter 50 of Gylfaginning, to punish Loki for his crimes, the Æsir turn his son Váli into a wolf and he dismembers his brother, "Nari or Narfi", whose entrails are then used to bind their father.
Eventually, Odin grew to regard Týr as a threat to his power, correctly suspecting him of plotting with the giants. As a result, Odin had Týr secretly imprisoned in Asgard and spread rumors that he had died. As a result, almost everyone in the Nine Realms believed Odin had killed Týr.
When Fenrir found that he could not break Gleipnir, he bit off Tyr's hand. The gods put a sword in Fenrir's open mouth to quiet him. According to legend, Fenrir will be released during the chaos just before Ragnarok, the final battle in which the gods of Asgard will be killed.
Angered, Odin declared war against the giants and sent Thor and other Aesir to commit genocide in Jötunheim. However, Týr helped the giants prevent Jötunheim from being reached by others, which resulted in the All-Father in imprisoning his son for betraying him.