Momoji is the lone successor of his family's craft, one of the three influential branches of the Iga ninja. He had lost his parents and siblings when he was barely old enough to comprehend his surroundings. Despite his personal hardship, he braved his ninja training when he was six years old and, after several years of training and missions, matured to be the finest shinobi of his home. He can use any ninja technique, but Momoji prefers to be an expert with hand-to-hand combat.

When he was twenty-one years old, the village had to lay two of their own to rest. Their lone daughter, Hotaru, wept uncontrollably by their grave. Momoji stood over her and patronized her to cease her crying as the dead won't come back to life. He left her when she insisted on wailing her sorrows until an order from the village elder brought him back. The elder gave him the responsibility of looking after the orphan and teaching her in her parents' absence. Momoji bluntly offered her the choice to either stay there or live as a shinobi. Hotaru stood and chose the latter. As he trained her rigorously through her protests, the pair soon bonded as they lived together. He would be called away for an occasional mission, but Hotaru would always anticipate his return to their home.