The Dark Horse website has an interview with legendary manga creator Kazuo Koike, author of Lone Wolf and Cub and many other classic manga. The introduction by Carl Horn is an essay in itself on the tension between commerce and art. In the interview itself, Koike talks about the difference between American and Japanese characters:
Japanese characters are strong in a different way from traditional American comics heroes; they have the strength to fight, but at their core you find tenderness rather than righteousness. A manga hero is a person, and good or evil, their fight is with other people. Their weakness isn’t some trick, some element or color, it’s that they’re people.
And he offers some advice to budding manga-kas:
What I always try to do is persuade my students to create a strong character first. If you have a strong character, the storyline will develop naturally, on its own. The storyline then follows in the character’s wake, and swirls around the character, influencing the character further.
The interview is well worth reading both for Koike’s creative insights and for his take on the place of manga in the Japanese society and economy.