| Category | Strongholds |
| Continent | Brucrumus |
| Region | High Wood Country |
| Owner | |
| Built | 28 Bliss 1714 |
| Map | Voternil |
Chain Jack was built in 1714 by a Maug construction company named Measure & Fortify. It is one of a string of immense fortresses that help impede the advancing Tendrils of Taurquion. Heavily fortified, Chain Jack is built with iron-clad timbers, a lot of metal, and concrete walls with reinforcing steel. These metal monstrosities loom over the landscape, looking like something of Mechanus rather than this world. Chain Jack is equipped with an array of machine-driven defenses and bristling with cannons. Another of its defenses are massive barbed chains built on spindles. When all of them are spinning, the place produces a humming that can be heard for many miles.