They can be upgraded with Flaming Shot.
Generally speaking, the Dwarves of Middle-earth don't have the urge to lay siege to their enemies—they are content to wall themselves in and ignore them. Yet, the Dwarves of the Iron Hills, more vulnerable and removed than some of their cousins, found themselves with the need of a weapon that could be mobilized, and as such, created the Iron Hills Catapult. The Dwarves of this area bordered the treacherous empire of Rhun, as well as the untamed reaches of the north, which meant that they would occasionally have good reason to knock down fortified encampments in order to clarify their border. Their propensity for construction yielded a weapon that worked as both a defensive device and an excellent siege weapon. To prevent the armies of Rhun from establishing permanent presence on their border, they mounted two catapult arms on one frame so that they could easily bombard structures from the hilltops and withdraw before a counterattack could be launched.
Built from: Forge Works at Level 2
Command Points taken: 25