Omura was a supplier to Clan Adachi who cheated the clan and was cut off, leaving his family in the streets. He died before the invasion and is buried outside Umugi Cove. His two sons joined the conspiracy and supplied the weapons for the massacre.
One son blackmails the conspiracy's leader for more money and arranges a meeting at Umugi Cove. Masako and Jin follow the brothers, who stop at their father's grave on the way.
The men waiting at Umugi beach kill both sons, on the leader's orders, before Masako and Jin can question them.