Who is Grant Kavanaugh from The Neutronium Alchemist Consolidation and what is their importance?

Grant Kavanaugh is Louise and Genevieve's father. He is the master of the vast Cricklade estate. When the city of Boston is threatened by a communist uprising, Kavanaugh leads the local militia to quell the attack. He is possessed by Quinn Dexter's former possessor, after Dexter manages to force him out of his body and into Grant's.