Vanessa E. Jones has an excellent piece on hip hop comics that discusses both American and Japanese comics that feature or include hip hop related themes.  I had not even heard of most of these comics, even though some of them are on track to do serious business, including development as film properties.

Special attention is given to Blokhedz and a familiar theme regarding hip hop enterprises arises, this time from a handful of hardcore comic book fans who responded to an interview with the twins who created Blokhedz:

"But 20 were, like, they were so disgusting," Davis says. "They said, ‘Black people don’t read; they watch BET.’ ‘This is never going to work.’ It was just straight ignorance. A lot of the diehard comic-book fans, traditionally they like their white hero and they think that [a black superhero] poses a threat to them. What made me feel better was a lot of my peers, a lot of artists I know from just seeing their work and stuff, they replied [to the critics], ‘You guys are ignorant.’ ‘It’s time to make this industry change; that’s why it’s not making any money.’ "

Let me repeat that last line in bold print:
That’s why it’s not making any money.

Comics name checked include: 
Afro Samurai
@Large
Ikebukuro West Gate Park
Worst
Tokyo Tribes

Not mentioned in the article but discovered while I was checking out the websites, is a guide to creating hip hop manga called Let’s Draw Manga: Tokyo Urban Hip Hop Culture from Digital Manga Publishing, publisher of Ikebukuro West Gate Park and Worst.

Actually these Japanese comics have very little to do with hip hop culture or rap music.  Gangs, guns and violent sex have a long world history that precedes hip hop music.  And the kind of sadomasochistic sex and rape fantasies portrayed in quite popular Japanese comics, that would be unacceptable on such a widespread basis in American culture, can usually only be found in the more extreme forms of gangsta and necro rap.