Love and loss is another theme. Dean has lost many people he cared about over the years. In fanfiction, his crying could be related to losing a love interest. Maybe he falls in love with a character, and then they are killed by a monster. His tears would then be a sign of his heartbreak and the pain of yet another loss in his already difficult life.
The trauma he has endured throughout his life is also a frequent theme. All the battles with demons, angels, and other supernatural beings have left their mark on him. In some fanfictions, he might cry when memories of past traumas resurface, like the time he was in Hell. It could be a moment of vulnerability where he can't hold back the tears any longer.
One common theme could be loss. Maybe Jo is crying because she has lost a loved one in the dangerous world of Supernatural. Another theme might be fear, like when she is faced with a particularly terrifying supernatural being.
Perhaps they are crying because they've reached a point of extreme exhaustion. After years of fighting, they realize they might not be able to keep going. Castiel, with his angelic nature but also his newfound humanity, and Dean, with all his emotional baggage, break down together, finding solace in each other's presence.
Friendship is a very common theme. Fans love to explore the unique bond between Charlie and Dean. Their friendship is different from Dean's relationships with other characters in the show, and fanfiction often delves into how they support and understand each other.
One common theme is mentorship. Dean often takes on a mentor - like role to Claire. For example, he teaches her how to hunt monsters more effectively.
One common theme is Dean's struggle with his vampiric nature. He's a hunter in the show, so becoming a vampire goes against everything he believes in. Fanfictions often explore how he deals with this internal conflict.
There are also a lot of emotional themes. For example, the idea of Dean having to protect Ben at all costs, or Ben trying to understand Dean's complex and often troubled past. These emotional elements add depth to the fanfictions and can make them really engaging.
There's also the psychological aspect. Dean might be tortured or held in isolation, and the fanfiction could delve into how he copes with that, his inner thoughts, and how it might change him as a character. This can add a lot of depth to the story.
Romantic relationships between them are also a popular theme. Writers might explore how a relationship between an angel (Castiel) and a hunter (Dean) would work, dealing with the differences in their natures, their loyalty to their respective worlds, and how they overcome obstacles to be together.
A lot of fanfictions also explore themes of sacrifice. Dean and Sam are often put in situations where they have to sacrifice something for each other or for the greater good. It shows their selfless nature. Also, the theme of redemption can be found in some, especially when they deal with characters who have made mistakes in the past.
Well, the theme of redemption is quite common. Whether it's Dean trying to make up for past mistakes or Sam finding his way back from a dark path. Love and friendship also play a role. Sometimes it's about their relationship with other hunters or people they meet. And of course, the struggle against fate. Many fanfics have them trying to break free from a pre - determined destiny.