After winning the second grand prize of 34th <i>Gessan</i> Rookie Award in April 2012, Kumagai made a debut with <i>Raihousha Ugin</i> at <i>Gessan mini</i> in March 2013. Kumagai later starts the first serialization with <i>Shuumatsu Fuuki Iinkai</i> at <i>Gessan</i> in Octobor 2013.
