
Quick answer — Hidekazu Himaruya worked on Hetalia: The Beautiful World (Original Creator), Hetalia: The World Twinkle (Original Creator), Hetalia World Series (Original Creator) and 3 more anime.
Hidekazu Himaruya worked on Hetalia: The Beautiful World (Original Creator), Hetalia: The World Twinkle (Original Creator), Hetalia World Series (Original Creator), Hetalia Axis Powers (Original Creator), Hetalia Axis Powers: Paint it, White! (Original Creator), Hetalia: World Stars (Original Creator).