Another theme is the concept of the outsider. Since vampires are not the norm in the 5ds universe, they are often seen as outsiders. The fanfictions explore how they try to fit in or change the existing order. They may face discrimination from other characters at first but then prove their worth through their dueling skills.
It could also be an internal identifier used by a company or a group. Maybe it's related to a game or a fictional universe that is not associated with adult themes. For instance, it could be a level or an area in a science - fiction based game.
There's a fanfiction called 'Vampire Allies in 5ds'. In this story, the vampires are not the typical antagonists. Instead, they form an alliance with some of the main 5ds characters. It shows how they use their vampire powers to help in various situations, like facing off against other powerful foes in the dueling realm.
Another good one is '999: Nine Hours, Nine Persons, Nine Doors'. It has a really interesting and mysterious plot. You are trapped on a ship with eight other people and have to solve puzzles and make choices that will determine your fate and the fate of others. The story twists and turns and keeps you on the edge of your seat.
For beginners, 'Phoenix Wright: Ace Attorney' is a great start. It has a simple enough gameplay mechanic where you just need to present evidence at the right time. The story is easy to follow and the characters are really charming. You get to be a defense attorney and solve some really interesting cases.
The novel 'The 34th Rule' is popular too. It explores the relationship between the Ferengi and the Bajorans in a unique way. It has some great plot twists and moral dilemmas that keep the readers hooked. It also gives a lot of insight into the cultures of both species within the DS9 universe.
Another one is 'The World Ends with You'. It has a unique setting in modern - day Shibuya. The story is full of mystery and the character relationships are really interesting. You play as Neku, a boy who has to fight in a strange game to survive, and as you progress, you uncover more about the world and its rules.
A DS novel is typically a type of fiction that might have some specific characteristics or be associated with a particular genre or style. But it's not a widely recognized or standard term.