Erebor Battle Master was completely overpowered in a Dwarf deck before his errata (spoiler alert: he still is). You could plop him down and he'd swing for a minimum of four for the rest of the game. As is, he takes a couple of rounds for him to get pumped up, but once you get your dwarf swarm going, the Battle Master rivals a Booming Ent trio. Just let him sit there, making Dain's boost look insignificant, staring down (up? he is a dwarf) orcs with that one eye of his.