Castiel's popularity on Supernatural gave rise to a rich and complex character that was both worthy of love and flawed. He showed great promise as the first angel to defy God's commands and choose free will. But choosing freedom led him to become more and more human, including making terrible mistakes and learning that not all bridges can be rebuilt.
But Cass has had his fair share of beatdowns from his fellow angels as well. Here are the five worst things Castiel has done to the angels, and the five worst things they have done to him.
10 CASTIEL HAS DONE: Killed Those That Didn’t Follow Him When in God Mode
After Castiel consumed the power of all the souls of Purgatory to gain control of Heaven, he became a merciless God without a shred of forgiveness for the factions of angels that defied him. Part of it may have come from the Leviathan's influence, as they were among the souls' energy he took in also.
But his hubris in believing himself to be the new God led him to smite his opposition. It was how he asserted his dominance and made the angels fear him.
9 DONE TO HIM: Uriel and Anna Tried to Kill Him
When Cass discovers Uriel's plan to allow the breaking of the Seals to release Lucifer, Uriel surprises him with an angel blade. They battle as Cass tries to save Dean from Alastair and survive Uriel's assassination attempt.
In the episode where they travel to the past, Anna is on a mission to kill John and Mary Winchester so that Sam and Dean are never born. She recruits a younger Uriel to get Cass out of her way as she knows he'll never allow her to extinguish the boys' existence.
8 CASTIEL HAS DONE: Stole Other Angels' Grace
After having his grace ripped from his vessel, Castiel finds himself human and dying. To survive, he steals the grace of another angel named Theo. It's a selfish moment where Cass cannot let go. He would rather kill a fellow angel than give up his mission to protect the Winchesters.
But the act is in vain, as stolen grace isn't permanent, and Castiel soon finds Theo's grace diminishing. If he had just waited, his grace would have recharged, but Castiel was impatient.
7 DONE TO HIM: The Trickster Gabriel Sent Him... Somewhere
In "Changing Channels," where the Trickster is revealed to be Gabriel, he sends Castiel away when he tries to save the Winchesters from TV Land. Dean demands to know where the Trickster sent Cass, but Gabriel's reply of, "Don't worry, he'll survive...maybe," does nothing to placate the older Winchester.
It's never revealed where Castiel was sent, but the fact that Gabriel didn't know if he would live or not shows how little he cared for his brother's safety. Thankfully, Cass did come back, albeit with a few scratches.
6 CASTIEL HAS DONE: Expelled the Angels From Heaven
Granted he didn't know he was dooming his brothers and sisters to fallen status, but they did still fall because of his actions. His belief that Metatron was doing the right thing by Heaven led him to follow the devious Scribe of God on his mission to dispel the angels from their home.
Regardless of his intentions, the angels still blamed Castiel for their fall from grace and sentence to life on Earth. Considering his tense history with them, it's easy to understand why.
5 DONE TO HIM: Metatron Used Him and His Grace for the Angel Tablet Ritual
Metatron knew that Castiel always believed the best in everyone and took advantage of that. He enlisted the wayward angel's help in completing tasks he claimed were to fulfill a ritual that would help Heaven, but he never specified how.
He deceived Cass so well he even got the angel to kill a Nephilim, an act that weighed heavily on Castiel. The final blow came when Metatron stole Castiel's grace to complete the ritual to expel all the angels. When Metatron's benevolent mask fell away, Castiel realized his mistake.
4 CASTIEL HAS DONE: Always Chose the Winchesters Over Them
Fans love the main trio that became Team Free Will, but the angels do not. Between picking sides in the Apocalypse to fighting factions trying to rule Heaven, Castiel always makes decisions based on how they will affect his relationship with the Winchesters.
He wants to please everyone, but ultimately his strong bond with Dean always gets in the way. When he finally becomes Heaven's leader, he sends the Winchesters away to appease his followers, but it's not enough. He gives up his leadership to maintain his friendship with Dean.
3 DONE TO HIM: Naomi Brainwashed Him
After Castiel forgoes leadership in Heaven as he wants to stay away from positions of power after his mistakes, Naomi takes advantage of his vulnerability. She uses him to spy on the Winchesters for her and lobotomizes him every time he makes a report so that he never knows he's playing double agent.
Worse still, she wants Castiel to kill Dean by his own hands, so she conditions him by having him murder clones of Dean multiple times until he can commit the crime without a second thought.
2 CASTIEL HAS DONE: Tried to Kill Jack Before He's Born
As the Nephilim offspring of Kelly Kline and Lucifer, Castiel believed Jack was a threat to the world. Though Jack is half-human, he is also half-angel, making him kin to Cass. The trenchcoat-clad angel is so convinced that Jack's relation to Lucifer spells doom for humanity and the Earth that he was willing to kill Kelly Kline to make sure Jack wasn't born.
This isn't the first time Castiel assumed a child with extraordinary powers could only turn to the dark side. He had a similar story arc with Jesse Turner, the supposed anti-Christ from season five.
1 DONE TO HIM: Lucifer Used His Vessel to Deceive the Winchesters
In his desperation to defeat the Darkness, Amara, Castiel turns to Lucifer for help. He says yes to letting the devil take over his vessel, but Lucifer lied when he said he could defeat Amara himself. Instead, he uses Castiel's vessel to deceive and torment the angel's best friends, Sam and Dean.
He also kills other angels using Castiel's powers, giving him more guilt to live with. Lucifer threatens to kill Sam with Cass's body and lie to Dean about why he did it. It's bad news all around with Casifer.