Hidekazu Himaruya has an Original Creator credit on Hetalia Axis Powers.
original creator
ONA / 2009
ONA / 2010
ONA / 2013
ONA / 2015
ONA / 2021
Special / 2011
OVA / 2013
OVA / 2010
OVA / 2014
OVA / 2021
ONA / 2026