I recently did some character design work for author (and friend) Will Derrick. The book is called Gokudo 893 and it's a crime thriller set in yakuza-controlled Japan. Haven't read it yet, but my copy is on the way!
You can order your copy at the website: www.gokudo893.com
Cedrina and Rydell
Katodanzo and Kenji Nodice
Sumo Wrestler and Tagaro
I'm currently taking commissions; hire me by clicking the "Order Custom Art" link.