Frank was the brother and former leader of Omega Squad
Frank commanded his little brother and Cpl Yor at the Ephyra Streets. He witnessed his brother get shot in the head. This filled him with rage, as he lashed out of cover cursing at the Locust. A grenade hit him in the back and got sharpenel in his back. He told Yor that he was the new leader, as three drones ran for Ilkin. He pointed the Hammer of Dawn at himself, killing him and the Drones.
His heroic death would lead to Yor being Omega leader, then Nate. Also the end of the two Ilkin brothers. Omega would never forget his sacrifice.