Darkest Dungeon

You will have to go through 3 “endless” rooms and have a camp at the end just before fighting the Miller. The areas are Farmstead enemies - one of the 4 regions - Farmstead - Boss. If you get the Mildred curio room she will give you a locket; equip this to your frontline hero (preferably a Leper) as it will redirect damage from The Reaping back to the Miller and increase the damage you do to him. Try to just focus him down, he will summon other enemies to help but they aren’t as big of a deal as his Reaping attack.