Well, clearly the OC Assassin is one of the main characters. This is a character created by the fanfiction writer, so they can have unique abilities, a distinct personality, and a backstory that sets them apart.
There could also be other assassins within the Dark Brotherhood who play significant roles. They could be rivals to the OC Assassin, competing for jobs or recognition, or they could be friends who support the OC Assassin through difficult times. Their relationships with the OC Assassin would add depth and drama to the fanfiction.
One interesting plot could be the OC Assassin's struggle to prove themselves within the Dark Brotherhood. Maybe they face challenges from other members who doubt their skills or loyalty.
In addition to Naruto, the Night Mother could be a significant character in this fanfic. She could be the one who has a special interest in Naruto, seeing his potential as a great asset or a threat to the Dark Brotherhood. And of course, Naruto's friends from the Naruto world might also make appearances in some way, either in Naruto's memories or through some sort of cross - world connection.
In the Dark Brotherhood story, there is often a Listener, who is a key figure in receiving the contracts. And there are assassins within the brotherhood, like the ones who carry out the kills.
I'm not sure specifically as it depends on the particular version of the 'Fall of the Dark Brotherhood Story'. But it could include leaders within the Dark Brotherhood and those who oppose them.
Voldemort often features prominently. Since he is the main dark wizard in the Harry Potter series, it's easy to incorporate him into the Dark Brotherhood concept. His power - hungry nature and his army of Death Eaters can be related to the workings of a dark brotherhood.
In many 'dark triumph assassin novels', the main characters are often complex individuals. For example, in 'Grave Mercy', Ismae is not only an assassin but also a woman trying to find her place in a male - dominated and often cruel world. She has to balance her loyalty to the convent that trained her and her own sense of right and wrong. Similarly, Celaena in 'Throne of Glass' has to deal with her past traumas while using her assassin skills to survive in a cut - throat world. And Mia in 'Nevernight' is driven by revenge, but also discovers more about herself and the world around her as she progresses in her assassin training.
One common theme is the Fem OC's journey of self - discovery within the Dark Brotherhood. She often has to figure out her place in this secretive and sometimes morally ambiguous organization.
Well, obviously there's Dark Gabriel. He is often depicted as a complex and powerful character. And then there's the OC, which stands for Original Character. The OC can be anyone the writer creates, with unique abilities, personalities, and backstories. For example, the OC could be a shy but extremely intelligent mage who catches Dark Gabriel's attention.
The Night Mother is often a very popular character. She is the spiritual leader of the Dark Brotherhood, and fanfictions like to explore her mysterious past and her connection to the Void. Writers often use her as a source of dark wisdom and prophecy in their stories.
Goodreads has some groups dedicated to fanfiction as well. While it may not be as well - known for fanfics as AO3 or FanFiction.net, you can still find some hidden gems. Join relevant groups, and post a request for 'Fem OC x Dark Brotherhood' fanfiction. You might be surprised at what you find.