Can you elaborate on this seemingly clear inspiration? Cause to someone like me who hasn't read much of early 2000s jump, it seems more like some baseless claim. The only inspiration I can see is Bleach, and that doesn't seem like something that would account for that whole era.
Bleach, D. Gray Man, Busou Renkin, Black Cat, etc.
Edgier, less whimsical series with a focus on a "cool" factor. We also had Death Note and Muhyo and Roji from the period.
Early 2000's had a notably distinct feel from other eras from Jump.
Even as whimsical and light hearted as Reborn! was it still had an edgy look with its mafia and firearms aesthetics.
I'm gonna write out a thing tomorrow comparing different periods in Jump so I'll elaborate more then.
I see us getting somewhere like that again though with The Promised Neverand, Jujutsu Kaisen, and the current directions of My Hero Academia Black Clover, and Kimetsu no Yaiba raising the stakes of their respective universes.