Sasuke could also be a great character to pair with Enma. Given Sasuke's dark past and his search for power, Enma could represent a different kind of power source that Sasuke might be interested in exploring. Maybe Enma has some knowledge about the Uchiha clan that Sasuke doesn't know.
A fanfic titled 'Enma's Secrets' could be a good one. It might uncover some hidden aspects of Enma's past, like his origins and his relationship with previous Jinchuriki. This fanfic could be filled with mystery and revelations that keep readers engaged.
Well, Enma Ai from 'Hell Girl' has a really tragic backstory. She was brutally murdered long ago, and because of the great injustice she suffered, she became the Hell Girl. Her job is to ferry those who are marked for hell. She has red eyes and long black hair, which gives her a spooky look. She doesn't really show much emotion, but deep down, she may still be haunted by her own past. When people summon her through the Hell Correspondence, they often don't fully understand the gravity of what they're doing, but she just follows the rules and takes the souls to hell.
Well, one possibility could be that Naruto gains unique combat skills. Enma might teach Naruto how to better utilize his chakra in more beast - like ways, since Enma has his own powerful chakra. Naruto could learn new forms of attack and defense, perhaps even a special jutsu inspired by Enma's own abilities.
Another great idea for a Naruto Enma fanfiction could be a story set in an alternate universe where Enma is a free - roaming entity and Naruto meets him by chance in a forest. Enma initially mistakes Naruto for an enemy but then realizes his connection to the Third Hokage. They then form an unlikely alliance to face a new threat that is emerging in the forest, which is endangering both the monkey clan and the nearby village.
I really like the fanfic 'Enma and Tsuna: Unlikely Allies'. It has a great plot where they start off as just acquaintances but due to certain events, they become really close. It shows their character development well, especially how Tsuna becomes more confident with Enma by his side. Another interesting one is 'The Enma - Tsuna Connection' which is more about their emotional bond and how they understand each other's feelings in a unique way.