He's only a half dragon, his mother was a hippopotamus! That's why he was banned from the city of dragons where only true blood dragons are allowed to life there. If you know that the author of the story, Michael Ende was his name, was german this gets a new dimension. It was a manifest against the nazi regime which says to the careful reader: Never let it happen again! Maybe that was one reason why he has chosen an black main character for his story.