In writing the story, I drew on several references from movies. In one, Contact, an effort is made to build a spaceship at great expense to make contact with an alien species. The ship is destroyed but later it is revealed that a second ship was built in case of a problem. John Hurt says, “First rule in government spending: why build one when you can have two at twice the price?”. I used that thinking with Garrosh’s plan to destroy Theramore. While they only had one focusing iris, wouldn’t they have wanted more weapons (even if less powerful)? Any goblin would say of course!
The background was that they had constructed two mana bombs but only one would use the focusing iris. If the iris failed to work as intended, or the zepplin was shot down, a second device was ready to be deployed (presumably on Stormwind). This echoes the development of Little Man and Fat Boy from the ending years of WWII. The modified zepplin, Hellscream’s Vengeance, was a nod to the Enola Gay – a highly modified (and stripped down) B-29 bomber. I took reference drawings from a Warcraft Zepplin and the design wound up similar to the custom zepplin used in the Theramore cutscene.
I used elements of models from World of Warcraft and adjusted them to make a customized zepplin – something more heavy duty for cargo or weapons use. It sported a modified base and light armor cladding, a reinforced ramscoop for the main jet, and a secured lower deck.