Bolg, Erebor's Reckoning

Trample At the beginning of each combat, other Goblins and Orcs you control get +2/+2 until end of turn. Creatures your opponents control get -1/-1 until end of turn.

His hatred for Dwarves smoldered for years after they killed his father Azog. When they killed the Great Goblin, the embers became a blaze.