A drunk marriage in Harry Potter fanfiction can be a catalyst for character growth. The characters who are 'drunk - married' may be forced to confront their true feelings for each other. They might have been friends before but the marriage situation makes them realize there are deeper emotions. There could also be external factors like other characters trying to take advantage of the situation for their own gain, or the magical contracts of the marriage having unforeseen consequences that the characters have to work through together.
Often, it starts with a wild party or celebration where too much butterbeer or some other wizarding drink has been consumed. Characters make hasty decisions and end up in a marriage situation. Then there's confusion and chaos as they realize what they've done.
In fanfiction, Harry Potter's psychology often gets explored in different ways. For example, his trauma from facing Voldemort and losing loved ones can be delved into more deeply. Some fanfics might show how he copes with the fame that he never really wanted, and his insecurities that are often masked by his heroic deeds in the original books.
In some fanfiction, the 'Power of Hate' might lead to the creation of new dark wizards or witches. Hate can be a catalyst for characters to turn to the dark side, much like how Voldemort was driven by his hatred. They might start using dark magic more freely and causing chaos in the wizarding world.
Well, in Harry Potter fanfiction, indifference and neglect can be a powerful theme. It can be seen in how Hogwarts itself might be indifferent to the needs of some students. There could be students who are neglected because they don't fit into the typical Gryffindor - Slytherin - Hufflepuff - Ravenclaw mold. This can result in those students either finding their own way to thrive or sinking into despair. Fanfic authors use this to explore different aspects of the wizarding world that the original books might not have delved into as deeply.
In Harry Potter fanfiction, manipulative behavior can be shown in many ways. A character might use lies and deception. For example, a character could lie about a prophecy to get others to follow their lead. They may also use emotional blackmail. Like a character threatening to expose a friend's secret if they don't do what they want. Another way is through false alliances. A character could pretend to be on one side while actually working for another, all to further their own goals.
Often, atonement in Harry Potter fanfiction involves characters making up for past mistakes. For instance, a Death Eater might try to atone by saving the lives of the good guys. It's about redemption and changing one's ways.
Indifference in Harry Potter fanfiction can create really unique storylines. For example, if Ron is indifferent to his family's expectations of him. Usually he's in the shadow of his brothers, but in this case, he could pursue his own interests, like maybe he becomes more interested in Muggle technology instead of pure wizarding things. This would lead to him having a different role in the group, and might even cause some conflicts as his friends try to understand his new direction.
Maybe the pens are enchanted and allow Harry to communicate with certain characters or access hidden knowledge. There could be all sorts of creative ways this plays out in the fanfiction.
In many fanfictions, the Jarvey is a comical character. It might use its sharp tongue to make witty remarks about the other characters, adding a bit of humor to the story. For example, in 'A Day with the Jarvey', it constantly pokes fun at the students at Hogwarts in a light - hearted way.
In many Harry Potter fanfictions, the 'darkly loyal' theme can be seen through character actions. For instance, a character might be loyal to a cause or a person that has a 'dark' aspect to it. They will follow orders or protect that entity without question, even if it means going against the general good. This could be like a follower of Voldemort who is so loyal that they will sacrifice their own moral compass.
In Harry Potter fanfiction, the 'daddy sucks' idea might be expressed through the emotional turmoil of a character. For example, Neville Longbottom could be shown as having a difficult time dealing with the memory or the reality of his father who is in St. Mungo's. The fanfiction could focus on how Neville feels let down by his father's absence in his life and how that shapes his character in a different way from the books.