Love. It's often a reason. Maybe he's being tortured because someone wants to get back at him for hurting their loved one. For example, if he broke a girl's heart who has a powerful father or brother, they might torture him to avenge her pain.
Past sins. Damon has a long history in the show. He has done many bad things. Fanfictions might explore scenarios where his past actions come back to haunt him. For instance, if he once betrayed a vampire clan in the past, they might finally catch up with him and torture him to make him pay for his betrayal.
One possible plotline could be that Damon is tortured by a powerful witch as revenge for something he did in the past. Maybe he accidentally killed a member of the witch's coven. Another could be that he is tortured by a group of vampires who want to send a message to Stefan. They might use vervain and sunlight to torture him in creative ways.
One common theme is the idea of an unlikely friendship. Since they have different personalities in the show, fanfictions often explore how they can form a deep bond. Another theme is adventure. They are usually thrown into some sort of dangerous or mysterious situation together.
A theme that is often explored is the idea of sacrifice. In many fanfictions, either Damon or Caroline has to sacrifice something - it could be their own desires, safety, or relationships with other characters - for the sake of the other. This theme adds depth to their relationship and shows the extent of their love and loyalty towards each other.
One common theme is redemption. Damon has a lot of past wrongs, and in many fanfictions, Bonnie plays a role in his journey towards redemption. For example, she might make him face the consequences of his actions in a more empathetic way.
One common theme is the exploration of a deeper emotional bond. Since they are brothers in the original show, fanfiction often delves into what if there was more to their relationship. Another theme is the struggle with their vampire nature in the context of a new relationship. For example, how their bloodlust might affect their feelings for each other.
Well, a frequent theme is redemption. Damon is a character who has done a lot of bad things in the Vampire Diaries, and in these fanfictions, the ofc often plays a role in his path to redemption. Supernatural power struggles are also common. Mason, being a werewolf, and Damon, a vampire, there are often power dynamics and struggles involved. And of course, friendship is a theme. The relationships between the ofc, Damon, and Mason can develop into strong friendships or something more, which is explored in these fanfictions.
One great Damon and Jeremy fanfiction is 'The Bond Beyond Blood'. It delves into how Jeremy, after his experiences in Mystic Falls, starts to see Damon in a new light. Their relationship evolves from one of distrust to a sort of begrudging respect and then to an unexpected friendship. The story is full of action and the typical Vampire Diaries drama.
There's a fanfic called 'Elijah's Redemption through Damon'. This one dives deep into Elijah's character development with Damon as an unexpected catalyst. It shows a different side of their relationship, more of a mentor - mentee kind of bond at times.
One great fanfiction is 'The Other Side of Midnight'. It delves deep into Damon and Elena's relationship, exploring their connection in a post - series world. It has some really interesting plot twists that keep you hooked.
I think 'Bonnie and Damon: Time - Twisted Love' is a great one. It involves time - traveling which adds a really cool twist to their relationship. Another is 'Bonnie and Damon: Body Swap' where they end up swapping bodies and have to deal with each other's lives. It's hilarious and also shows a different side of their connection. And 'The Inverted World of Bonnie and Damon' where the rules of the vampire and magic world are inverted for them.