Stay diagonal to avoid its ice beam. Use Assassin Stars and Exori San. A team of 2 or 3 is recommended so you can kill 3 or more Ice Overlords. A paladin normally has time to solo 2 overlords per 8 ice soils. There is a spot in the south-east corner where you can go diagonal and the overlord can't hit you with the beam. It's better to kill the last overlord in there.