The Planarch Vault

From Introduction:

Created as a joint venture between the gnolgi and the templars, the Planarch Vault is a prison complex and archive for monsters and treasures too powerful to keep anywhere else.

It has been overtaken by two of its worst inmates: a villain from another reality and a horde of quasi-mechanical shapeshifters. The shapeshifters want to cause as much trouble as possible; the villain intends to use the shapeshifters as a distraction to escape and fulfil their own agenda.

The vault’s path has taken it within an inch of the capital; only to land a few leagues south in the wetlands. The templars have mobilised to secure their secrets and discover the fate of the wardens within.