Well, in the MHA manga, Dabi does meet his end. It's a poignant moment that has significant implications for the story's progression and the dynamics among the characters.
Midoriya Izuku could also have an interesting reaction. He's always trying to understand the villains better, and Dabi is a very mysterious villain. He might study the fanfictions to look for clues or insights into Dabi's character that he could use in a potential confrontation or in his quest to become a better hero. He might be surprised by some of the creative interpretations in the fanfictions.
First, study Dabi's character in the original BNHA. Notice his mannerisms, his dialogue style, and his relationships. Then, come up with an interesting plot. It could be about his past, his future, or a 'what - if' scenario. For example, what if he joined the heroes? Next, create engaging characters to interact with Dabi. And don't forget to add some action and emotional depth to keep the readers hooked.
The ending of the MHA manga was quite intense and had some unexpected plot twists. Heroes and villains had a final showdown, and the fate of the characters was determined.