The fourth mission, The Price of Iron, is built around a rescued building called the Brassworks. Until this week it was a stand-in Workshop. The Foundry Annex replaces it: the first building that belongs to one clan, the Bronzebeards, and the place where the siege Ram is trained from now on.
Drawn from the Forge
Rather than prompting a new building from nothing, the candidates were edited from the Forge's own accepted source image, so the masonry, roof tiles, banner and light all match the buildings already standing. Three shapes came back: a gantry crane over the yard, an open casting floor with a glowing crucible, and a heavy gate. Each has a real construction frame and shares the Forge's rubble when destroyed.
Complete, not just drawn
A building here is not done when it looks right. This one exists end to end: a content record, generated engine scripts, an editor catalogue entry, a worker build button gated behind the Forge, the Ram's training moved to it, the mission rebuilt with it in place, and the mission's twelve scripted scenarios re-run and passing. Its hit points were deliberately held equal to the old stand-in so the mission's passive-loss timing did not move.
Which of the three shapes is the Annex is still an open pick. The game currently runs the recommended one.