Toshimitsu is one of the seven ninja dogs serving Tesshin. In the Hougen arc, Toshimitsu stays with Buruge while they wait for reinforcements, trying to push Hougen off the cliff. Hougen threw Buruge down the cliff and overpowers Toshimitsu who survives when more reinforcements came. In The Hokkaido arc, he was sent by Tesshin to gather other dogs to help take down the russian army. He found Kyoushiro, Teru and the puppy ninjas. Before Tsukikage could get killed by the Russian dog soldiers, Toshimitsu, Kyoushiro, Teru and others managed to arrive on time and drove the Russian dog soldiers away.

In GDW:O, Matheus takes over Koga and forces Samu, Elder, Tsukikage and Toshimitsu to jump into a waterfall. Toshimitsu survived the jump.