Restoration is also a theme. Castiel is often in a weary state in the series, so in fanfics about his sleep, it can be a time for him to regain his strength, both physically and mentally. His sleep is seen as a way to heal from the many traumas he has endured throughout his time on Earth, whether it's from battles with demons or the internal struggles within the angelic hierarchy.
One common theme is vulnerability. When Castiel is sleeping, he is in a state where he is unguarded, and fanfics often explore how this vulnerability affects him and those around him.
Another theme is the mystery of his dreams. Since Castiel is an angel, his dreams might be different from human dreams. Fanfics like to play with this idea, showing his dreams as visions of other realms or prophecies. For example, some fanfics depict his dreams as glimpses into the future of the Winchester brothers' battles.
Love and friendship are also very common themes. Whether it's a platonic love or a more romantic love, it's often explored. In some fanfics, they have to hide their feelings from others, which adds an element of secrecy. And then there's the theme of sacrifice. They are both willing to sacrifice themselves for the greater good and for each other.
Rescue scenarios are also popular. Other characters, usually Dean, might come to his rescue. This can create a lot of tension and drama in the story. It can also be a way to explore the bond between Castiel and the rescuing character, with a lot of emotional moments as they reunite.
One common theme is Castiel's struggle with his angelic nature. He often has to balance his loyalty to heaven and his newfound connections with humans.
Another theme is growth. In these fanfics, Castiel usually grows as a character. He might learn about human values like love, friendship, and loyalty in a more intimate way since he's part of a family. For instance, he could start to understand the concept of a family dinner and the significance of sharing time with loved ones.
One common theme is power. Since Castiel is an alpha, his power is often explored, like how he uses it to protect or lead. Another theme is loyalty, as in how his pack or those around him are loyal to him, and vice versa.
One common theme is identity. Since Castiel is usually male in the original series, when she's female in fanfiction, there's a lot of exploration about how she sees herself and how others perceive her. For example, some fics show her struggling with the new body and the expectations that come with it.
The theme of sacrifice also pops up a lot. Castiel may have to sacrifice his angelic duties or powers for his wife, or the wife might sacrifice her own safety or desires for Castiel. This creates a sense of drama and emotional depth in the stories. For instance, in one fanfic, the wife gives up her chance at a normal life to stay with Castiel in the dangerous world of angels and demons.
One common theme is friendship. Their bond, whether it's a platonic friendship or something more, is often explored. Writers like to show how they support each other through tough times.
One common theme is redemption. When Castiel is hurt, often the story will revolve around him finding a way to redeem himself, whether it's from a mistake he made that led to his pain or just from a sense of lost purpose. For example, in some fanfictions, he might have been hurt because he trusted the wrong entity and then has to make amends.
One common theme is friendship. Since both Castiel and Cassiel are often portrayed as angels, their bond of friendship is a key aspect. Another theme is redemption. Many fanfics explore how they can redeem themselves for past actions.