The Marvel Cinematic Universe has produced many iconic characters and villains, many of which are more complicated than simply good or bad. As Loki explains in his Disney+ series, "No one bad is ever truly bad. And no one good is ever truly good." The second part of that statement expertly describes his adoptive father, Odin, who is arguably the MCU's most overlooked villain.
Introduced in Thor, Odin actually doesn't appear onscreen much during the runtime of the MCU, but the amount of damage he causes in that time is astronomical. To start things off, for some inexplicable reason, Odin left the Tesseract on Earth to be stowed and virtually unprotected by mere humans. That left the containment vessel for the Space Stone vulnerable; it was (much later) easily attained by the Red Skull and Hydra. Not only did the Red Skull use the Tesseract to murder countless people, but he also killed countless others in pursuit of the treasure. In other words, Odin used those people as sacrificial pawns for no discernible reason.
Odin Is a Conqueror of Worlds and a Terrible Father
Then there's the fact that he's a conqueror. Played by Anthony Hopkins, Odin is the King of the Nine Realms only because he seized them by force. He was not a benevolent leader but a ruthless tyrant, and on his crusade, he brought with him his eldest child, Hela (Cate Blanchett), who served as his commander and executioner. He used her in his pursuit of power and then banished her for doing exactly what he conditioned her to do. When her ambition outgrew his, instead of taking responsibility for his actions, he locked her away.
He's not only a terrible father to Hela but to his sons as well. First, he raises Thor (Chris Hemsworth) to be a warrior king, and then he becomes angry and disappointed when his son grows up to be just that. Moreover, Odin's banishment of Thor is at least as brash as his son's initial charge into Jotunheim. Thor's decision was arguably better thought out than Odin's punishment because he at least consulted with others first. Conversely, Odin made his decision on instinct and actively chose to ignore the input of Loki (Tom Hiddleston) when he tried to interject on Thor's behalf.
That then leads to the simply unforgivable way Odin raised Loki. He told Loki all his life that he was born to be a king but didn't actually explain anything about his heritage and, therefore, fostered an environment of jealousy and competitiveness between his sons. Loki's true origin should not have been kept from him, especially when it clearly influenced the way Odin treated his adoptive son. Loki's insecurities and bad decisions are directly linked to Odin's terrible parenting.
In Thor, Loki let the Frost Giants into Asgard to mess with his brother because Odin created animosity between the siblings. Then Loki confronted Odin about his hidden parentage and saw himself as a monster, which exacerbated his already-vulnerable state. Odin's reaction to that understandable rage is to fall into the Odinsleep instead of facing the consequences of his actions. In doing so, he gives the throne to Loki when he's at his most angry and vengeful.
Odin Is Responsible for Loki's Turn From Trickster to Villain
That leads to Loki creating an over-the-top scheme to destroy the Frost Giants and prove himself the rightful king of Asgard. In his final showdown with the newly returned Thor, Loki actually admits that he never wanted the throne; he just wanted to be Thor's equal. If Odin was a better father, then Loki could have felt equal to Thor, and this standoff might never have happened.
If this were the case, Loki wouldn't have ended up hanging off the edge of the Rainbow Bridge, which is where Odin doubles down on his atrocious parenting and rejects Loki's desperate plea for approval. That's the reason Loki lets go and falls through space, only to then team up with Thanos and launch his assaults on Midgard, culminating in the Battle of New York. So really, Odin is the big bad behind Loki in The Avengers, even more so than Thanos.
Odin Responds to Grief With Revenge, at Any Cost
That brings us to Odin's dismal behavior in Thor: The Dark World. An alternate deleted scene shows him just standing by and allowing Malekith to kill Frigga (Rene Russo) instead of surrendering the Aether. He puts down his weapon right after Frigga begs him to kill Malekith. There is something to be said about protecting the Infinity Stone, but after spending so much of his life as a warrior king, this is a bizarre time to choose a passive resolve. Thor leaps into the scene ready to fight for his mother, although he's tragically too late to do so. Odin has no such excuse.
That scene was scrapped. However, Odin's canonical onscreen behavior is little better. His reaction to Frigga's death is revenge against Malekith, with little regard for how many of Asgard's warriors it may cost. He continues to be a bad father in keeping Loki prisoner and not even allowing him to attend Frigga's funeral. Odin also refuses to listen to Thor's plan to go after Malekith and instead wastes time and resources to his own detriment. So he's not just a bad father but a bad leader as well.
Odin's Lifetime of Brash Decisions Ultimately Leads to Ragnarok
In Thor: Ragnarok, Odin is dying when Loki and Thor catch up to him. He finally tells his sons that he loves them sincerely, the same sons he's banished, lied to and imprisoned at various times. The moment is a noticeable shock to Loki, which is a pretty clear symbol that he's a bad father. On his deathbed, Odin suddenly gets all warm and New Age-y as he explains that Asgard is a people, not a place.
Only then does Odin admit that Hela is coming to seek power and revenge because he, inexplicably, tied her banishment to his own lifeforce; when he dies, she is automatically released from her prison. That makes his mistakes someone else's problem in the most destructive way possible. His delay gives the brothers, and all of Asgard, no chance to prepare for Hela's arrival and, therefore, the only way to defeat her is to allow Ragnarok to unfold, which results in the deaths of nearly 10,000 Asgardians.
Odin is a terrible king, a thoughtless husband, and an even worse father. His actions and behavior cause more death and destruction than nearly any other MCU villain, and he's supposed to be one of the good guys.