Dragon FIst

The series follows Ling Fei-long, a Chinese transfer student living in Japan. Ling is the son of the leader of the White Dragon clan, one of four clans who live in the mountains of China and are descended from mythical beasts. After killing an ordinary human, Ling is banished to Japan so that he might learn about humanity and how to control his powers around them.

This particular manga has been published one volume per year for the past 12 years, so the artistic style changes rather drastically as you read further on. It's a kind of chronicle of Katayama Shuu's growth as an artist.