The Hitman Reborn manga ended with a climactic battle and resolution of the main character's story arcs. But it's a complex ending that's best discovered by reading it yourself.
Fanfiction in these two can be about relationships. It could be romantic relationships, like shipping certain characters in Katekyo Hitman Reborn. Maybe a story about Gokudera and Yamamoto's friendship evolving into something more. In Dark Hunter, it might be about the complex relationships between the hunters and the creatures they hunt. There are also action - packed fanfictions that expand on the battles and combat scenarios in both series.
One possible fanfiction could be where Tsuna and Chrome go on an adventure together to find a special item in the Katekyo Hitman Reborn world. They might face various challenges along the way and their relationship could grow stronger as they rely on each other's skills.
The Katekto Hitman anime is moderately in line with the manga. It keeps the core story intact while making some adjustments to make it more appealing for the anime format.
A popular theme in Katekyo Hitman Reborn fanfiction is power - up. Fans like to write about Tsuna and his friends getting new powers and how they use them to face tougher enemies. In Dark Hunter fanfiction, the theme of redemption is quite common. Many stories explore how a hunter who has made mistakes in the past tries to make up for it. Another shared theme could be loyalty, as both series have strong elements of loyalty within their groups.
Yes, there are quite a few interesting ones. You can start by looking on fanfiction websites like FanFiction.net or Archive of Our Own. Just search for 'Harry is Renato Katekyo Hitman Reborn' and you'll likely find some stories that blend the two universes in creative ways. Some might focus on how Harry's character traits interact with the world of Katekyo Hitman Reborn, creating unique plotlines and character dynamics.
The unique character design of the thief OC. If the writer creates a complex and engaging character with a distinct personality, backstory, and set of skills related to thievery in the 'Hitman Reborn' universe, it can be really interesting.