I'm not sure specifically which 'Dizzee' you are referring to. There could be many people with that name. If it's a well - known public figure, more context is needed to tell the full story of the stabbing.
One reason could be revenge. Maybe someone he wronged in the past, like a fallen angel or a demon he betrayed, decides to take their vengeance by stabbing him. It adds a layer of drama to the story.
One interesting fanfiction could be 'Lucifer's Trial by Blade'. In this story, Lucifer gets stabbed during a battle in the underworld. The author vividly describes his pain and the chaos that ensues. It's a great read if you like action - packed fanfics.
One possible consequence is that Naruto could be severely injured. This might lead to him losing his ability to fight for a while. His friends would then have to step up to protect him and the village.
Toge Inumaki is important too. His special cursed speech ability makes him stand out. Also, the principal of the school, Masamichi Yaga, is likely to be important as he is in a position of authority and has an influence on Gojo and the other students. There could be other characters like the members of different clans that also play roles in the complex web of the story.