Since I haven't read it, I can't say for sure. But based on the title, the main characters are likely to be the 'oroka na tenshi' (the naive angel) and the 'akuma' (the devil).
I'm sorry, I haven't read this light novel specifically. But generally, from the title, it might be about an 'oroka na tenshi' (a naive or simple - minded angel) that has some sort of interaction with an 'akuma' (devil) and they 'odoru' (dance). It could be a story full of supernatural elements, with a plot centered around the relationship between these two opposing beings, perhaps exploring themes like good vs. evil, redemption, or the blurring of moral boundaries.
I'm not sure exactly what this light novel is about as it's not a widely known one to me. It could potentially be about the relationship between a master (kainushi) and a female high school student (joshikousei) in a sort of pet - like dynamic. But this is just speculation without further information.
Harry Potter himself is a likely candidate. Given his heroic nature and the need to constantly fight against dark forces, an Akuma no Mi could be a great addition to his arsenal of skills. It would give him new ways to protect his friends and defeat his enemies.
I'm not sure where you can find this specific light novel. You could try checking some Japanese - focused bookstores, both physical and online. Maybe websites that specialize in Japanese light novels or anime - related merchandise might have it.
Well, the Akuma origin story could be related to ancient curses. Maybe it was a result of a forbidden ritual gone wrong. In certain tales, Akuma is seen as a manifestation of the darkest human emotions. It gains its power from fear, anger, and hatred, and over time, it has evolved into a terrifying force that preys on the weak and the vulnerable.
I'm not sure if there is a specific fanfic exactly like that. There are so many Naruto fanfics out there, and while some might involve Naruto having an interest in Akuma in some creative crossovers, it would take some serious searching through fanfic platforms to find one.
Well, akumas typically have a back story related to a source of evil or a corrupting influence. It could start with a character who has some sort of inner turmoil or a tragic past. This internal struggle makes them vulnerable to the influence that turns them into an akuma. For example, if a character has lost a loved one and is filled with grief and anger, that might be the trigger for the akuma transformation, leading to a whole new set of actions and a role in the story as an antagonist.
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.