He worked at Blizzard North on the Diablo franchise for over a decade. He was the Lead Artist for the first version of Diablo and created the concept design for the majority of the characters and monsters in the game, including Diablo himself.
On Diablo II, Okamura was a Senior Artist, and created character and monster concept designs, including the second incarnation of Diablo.
After Diablo II, Okamura worked as an Art Director establishing the pipeline and creative direction for several internal projects, and then joined Castaway Entertainment in 2004. In 2005, he founded and was president of Hyboreal Games with former Blizzard North employees Eric Sexton and Steven Woo. Hyboreal changed its name to U.I. Pacific, and as of 2007, Okamura is Creative Director.