Railmaster Pauli Rocketspark, chief foreman of the Grimrail Depot, has been enlisted by Garrosh Hellscream to build the technology required for the Iron Horde's infrastructure. Given the dim-witted assistant Borka to do the heavy lifting, Rocketspark set about building the Grimrail.
With a zeal for flame and explosives, Nitrogg was a natural fit in the mechanized and weaponized army that Garrosh's plans brought to Draenor, and he has risen quickly through the Iron Horde. He oversees the artillery on the Grimrail, and is eager to break through the defenses around Shattrath and conquer the enemies of the Iron Horde within.