Rohan Kishibe

Rohan Kishibe (岸辺 露伴) is a character introduced in Part IV: Diamond is Unbreakable. Being a successful mangaka by profession, it is likely that he's a self-insert of Hirohiko Araki. The name Rohan Kishibe also appears to be an anagram of the author Araki Hirohiko. Rohan's name shares enough letters to spell "ARKI HIHO", and duplicating the missing letters in "O,R,A,I,K" would complete "Araki Hirohiko."