One popular trope is the 'First Kiss' trope. It often builds up a lot of tension between Castiel and Dean before they finally share that first, passionate kiss. Another is the 'Forbidden Love' trope, as their relationship within the context of the show has many obstacles, and this is often explored in fanfiction with their kisses being something that goes against the norm or is kept secret.
The 'In - the - Heat - of - the - Moment' trope is frequently seen. For example, during a dangerous situation, Castiel and Dean might suddenly realize their feelings and share a kiss. It adds an element of spontaneity and urgency to their relationship. Additionally, the 'Reconciliation Kiss' trope is popular, especially after an argument or a period of separation. Their kiss becomes a symbol of forgiveness and a new start in their relationship.
The 'Soulmate' trope is also quite common. In these fanfictions, Castiel and Dean are fated to be together, and their kisses are a powerful manifestation of their deep - seated connection. It might involve some supernatural elements related to the idea of soulmates. There's also the 'Angst - filled Kiss' trope, where there are a lot of emotional turmoil and problems between them, and the kiss is a moment of both pain and love, often filled with unspoken words and feelings.
The 'alternate universe' trope is quite common too. For example, there are fics where Dean and Castiel are in a modern - day high school setting instead of the supernatural world they're usually in. It gives a fresh take on their characters and relationship.
Well, 'The Unspoken Love' is also quite well - known. It's a slow - burn story where the kiss is the culmination of many small, tender moments between Dean and Castiel. It shows how their relationship has been building gradually, like a slow - growing flame.
One popular trope is the 'hurt/comfort' scenario. For example, Dean gets injured on a hunt, and Cas takes care of him, which leads to a tender moment and a kiss. It plays on the emotional bond between them and the protectiveness they feel for each other.
A common aspect in such fanfiction could be the build - up of emotions. Dean and Castiel have a complex relationship throughout the series. Their first kiss might be a culmination of unspoken feelings, perhaps after a dangerous situation where they realize their true feelings for each other. It could also be a moment of great vulnerability for both characters, as they break through the barriers of their friendship or comradeship.
Another theme is the redemption arc for Castiel. In these fanfictions, Dean plays a crucial role in helping Castiel find his way back from any dark paths he may have tread. For example, some stories show Dean standing by Castiel during his struggles with his angelic nature.
One possible theme is the exploration of forbidden love. Given their different natures (Dean being human and Castiel being an angel), their relationship might be seen as something that goes against the natural order in the context of the show's universe. The first kiss then becomes a bold statement against those restrictions.
Often, the theme of sacrifice is present. Maybe one of them has to make a big sacrifice for the other, and the kiss is a moment of intense emotion before or after that. It could also be about them breaking free from some kind of supernatural constraint that has been holding them back from being together, and the kiss is a symbol of their newfound freedom.
One popular story could be 'The Bond Beyond Worlds'. It delves into a deeper connection between Dean and Castiel, exploring their relationship in a post - apocalyptic setting. The story is known for its intense emotional scenes.
There are fanfictions with the theme of alternate universes. In these stories, Dean and Castiel experience different versions of their relationship. For example, in one universe they might be rulers of a supernatural kingdom, and in another they could be ordinary humans. These themes add a lot of variety and intrigue to the fanfictions.
The 'Forbidden Love' trope is quite common. Given Castiel's angelic nature and the rules in the Supernatural world, a relationship between him and a human reader might be seen as forbidden. This adds an element of tension and drama to the story. Also, the 'Healing' trope, where the reader helps Castiel heal from his past traumas or vice versa, is often used. They support each other through difficult times, which makes for a heart - warming story.