Another place is FanFiction.net. There are some really good and unique 'Akuma no Riddle' fanfics there. Just use the search bar and type in 'Akuma no Riddle' to find relevant stories.
One great 'Akuma no Riddle Fanfiction' is 'The Unspoken Bond'. It delves deep into the complex relationships between the characters. The author does an amazing job of exploring the emotional depth that the original series only hinted at.
Since I haven't read this particular 'akuma no riddle banba fanfic', it's hard to say for certain. However, generally in fanfics for 'Akuma no Riddle', they often explore the relationships between the characters in more depth. Maybe this one with 'Banba' focuses on his backstory, or his relationships with other characters in a way that the original work didn't fully explore.
The fanfic might focus on the unique dynamics between Tokaku and Haru. For example, it could show how their personalities, one being more reserved perhaps (Tokaku) and the other more open (Haru), complement each other. It may also explore their shared experiences and how those shape their relationship within the story.
There could also be an antagonist or a group of antagonists. They would be the ones creating obstacles for the main character and other protagonists. Their actions and motives would be crucial to the development of the mystery and the story as a whole. They might be trying to prevent the riddle from being solved for their own gain or to maintain some sort of power or control within the world of the light novel.
One great Akuma no Riddle crossover fanfiction is 'Akuma no Riddle Meets Another School'. It combines the unique characters from Akuma no Riddle with a different school setting, creating interesting new dynamics. The interactions between the assassins and the new characters are really engaging.
The 'riddle story of devil fanfiction' could be about a lot of things. In fanfiction, the concept of a devil can be very diverse. It might be a modern - day setting where the devil appears and gives riddles to a group of people for his own amusement or some grander plan. The riddles could be related to things like human nature, morality, or the secrets of the fanfiction universe. The story could also involve characters trying to outwit the devil by solving the riddles, which could lead to different endings depending on whether they succeed or fail.