Why Thor and Jormungandr Hated Each Other?
We might know that in the battle of Ragnarok, Thor and Jormungandr were destined to kill each other. But the question was why Thor and Jormungandr hated each other.
Background
The first reason we have to consider is the origins of them both. Thor came from the god tribe for he was the son of Odin the Allfather whom probably all of the giants hated the most in Norse Pantheon. Meanwhile, Jormungand was the son of Loki the Trickster who lived among the gods.
Although Loki lived with the gods, no one really revered him. May we say that Loki had to spend most of his time living by the emotions of others.
Many sources mentioned Loki came from the giants and he was the pure giant himself. Were this mythologically true, the background of Jormungand and Thor was the initial reason why they hated each other that much.
Competition in Utgard-Loki
In Norse mythology, Thor and Loki once had a chance to travel to the land of Utgard-Loki. When the gang arrived at the gate of Utgard-Loki, they were not welcomed by the giants in Utgard-Loki. The gods were even laughed at because they appeared to be too small. In his anger, Thor agreed to take part in competitions against the giant in the hall.
Thor attempted to lift up Jormungand the Serpent
Thor was challenged by the king of Utgard-Loki to lift up the cat in the hall. However, much to everyone's shock, Thor could only lift up the paw of the cat. Next, Thor competed in the drinking contest for he was famous for his drinking skills. Yet, he could not finish the drinking horn handed by Utgard-Loki.
Later, when Thor left Utgard-Loki, the giant king said that it was all set up. The cat that Thor attempted to lift up was actually Jormungand the Midgard Serpent. At that time, Jormungandr was so enormous that he encircled the whole Midgard. And the drinking horn that Thor drank was connected with the ocean. And when Thor quit the drinking contest, he did drink up half of the ocean water.
This truly ignited a fire to win against Jormungand
Thor fishing Jormungand
On one occasion, Thor had a chance to go fishing with a giant named Hymir. Thor had very special bait for the fish he was about to fish. The bait was a head of an ox and off the pair went to the vast ocean.
Biding the time, Thor finally felt a wave in the ocean surface and his rod shook a little bit. Quickly grabbed the rod, he knew that the "thing" that just got baited was no joke. It turned out to be that "thing" was Jormungand the Midgard Serpent. Thor who was still angry for losing the competition in Utgard-Loki this time determined to kill Jormungand.
However, Hymir the giant that went with Thor was afraid of the prophecy. In Norse mythology, the prophecy said that when Jormungandr lifted himself from ocean waves, there came the time of Ragnarok. Hymir was afraid that Ragnarok was about to come when Thor pulled up the serpent, he cut off the fishing line which also meant he released Jormungandr.
Thor fishing trip
Regarding Thor at this time, he quickly grabbed his Mjolnir hammer and was about to smash the hammer on the serpent. Much to his surprise, his useless companion cut the fishing line and Jormungand just slipped away.
Thor's surprise quickly became anger and he pulled them all out on Hymir. He threatened to kill Hymir. But all Thor did was throw Hymir off the boat and sailed the boat back to shore himself.
Conclusion
For the three stories mentioned above, we believe that they are the possible reasons for why Thor and Jormungand hated each other. The hatred was so great that the pair finally determined to slay the other in Ragnarok. And legend had it that they did kill each other in their final battle. If Odin and Fenrir became sworn enemies for Odin's cautions against Ragnarok, Thor hated Jormungand for his Midgard Serpent was the only one in the cosmos that could be a challenge for him.
loki was probably in the back like “Really Thor why you like this if only you knew thats my son you imbecile”