A younger brother who is more shy and reserved compared to the others could be an interesting character to focus on. His experiences with the brides might be different from his more outgoing brothers. Maybe he has a hard time expressing his feelings at first, but as the story progresses, he opens up more. This character arc would be engaging to write about.
The eldest brother could be a great character to focus on. He's usually the leader among the brothers, so exploring his thoughts and decisions would be interesting. For example, how he decides which bride is right for which brother and how he manages the family as new brides come in.
One idea could be exploring the backstories of the brothers more in - depth. For example, how they learned their skills like hunting and building. Another could be a modern - day retelling of the story, with the brothers and brides in a contemporary setting, dealing with modern problems like technology and social media.
I think Ruby would be really interesting. Her optimistic and fearless nature in RWBY would contrast well with the often dark and power - based world of Overlord. She could bring a sense of hope and naivete that would either endear her to the Overlord characters or make her a target. Also, her scythe - wielding skills and her use of her speed Semblance could be unique in the Overlord world.
Percy himself would be a great choice. Since he's the main character in the original series, readers are already familiar with him. You could explore his relationships with his friends in more depth, like his loyalty to Annabeth and his brotherly bond with Grover.
The main character is most likely the bride herself. Since it's a 'bride's story', she would be the central focus.
Ema Hinata is often a central character. Since she is the main female character in the original work, many fanfics tend to focus on her relationships with the brothers. Subaru Asahina is also quite popular. His passionate and sometimes brash personality can create interesting storylines in a lemon fanfic.
Another option could be Ronald Speirs. His mysterious and tough - as - nails personality would make for an exciting character in a 'Kuroinu' - like setting. He could be the one who is not afraid to take on the most dangerous foes in 'Kuroinu' and his actions could drive the plot forward.
Philip and Elizabeth Jennings are obvious choices. Their complex relationship and double lives are full of potential for fanfic exploration. You can create scenarios that further test their loyalty to each other and to their country.
Jack is a great character to focus on. He's the main character, so there's a lot of material to work with. His growth in martial arts and his relationships with the other characters are rich areas to explore. For example, you could write about his struggle to master a new move and how his friends help him.
I think focusing on the Wattersons family as a whole can be really interesting in a Gumball fanfic. You can show their family dynamics, like how Richard's laziness affects the household, or how Nicole's strictness is both a help and a hindrance. Then there are the friends like Carrie, the ghost girl. Her spooky nature and her friendship with Gumball and the others can add a unique element to the story. And Tobias, with his one - sided crush on Penny, can also bring in some elements of unrequited love and jealousy into the fanfic.
Often, the two brothers themselves are the best characters. Their relationship forms the core of the fanfic. But sometimes, side characters can also be really great. For example, a wise old mentor figure who guides the brothers can be a really interesting addition.