Atsumori is actually one of the nobles of Genji's enemy, Heike. He was rescued and protected by the Miko when found lay dying on the battlefield. Atsumori is a very quiet boy that keeps to himself. Atsumori joined the Genji side as a traitor to Heike to fulfill his dream, put an end to this war and destroy all the Onryou raised by Heike.

Although Atsumori made the choice to betray his family for the good, he was constantly troubled and saddened when he was forced to put an end to the people he knew. Unfortunately, Atsumori never expressed the ache in his heart to the rest of the group and endured it all by himself.