The Mansions · GM Reference · Portal Instability

When the Portals Opened

The first time the family opened all three portals, the Mansions did not shake. They misremembered themselves. A room kept its windows but lost its walls. A door opened onto the shape of a hallway that had never been built. Somewhere above, a stair continued into open air.

The Veyr family built the miniature rifts as controlled apertures: Ash to Fire, Glass to Air, and Thorns to Earth. The portals were never meant to become roads. When the family opened them together, however, the three pressures began to interfere with the Mansions’ boundaries. Fire softened stone, air displaced distance, and earth pulled rooms toward older foundations.

What destabilization looks like

Rooms without doors: Some rooms can be reached only through a window, a stair that appears for a few minutes, or a wall that becomes transparent at the right angle.
Doors to nowhere: A familiar door may open onto darkness, open air, a blank wall, or a room from another Mansion. The frame remains real even when the destination does not.
Windows as entrances: Windows are not merely scenery. An opening may be the safest route into a room, especially when the normal door has been displaced.
Rearranged thresholds: Entrances and exits sometimes trade places. A party can leave by the same arch it entered, but arrive in a different corridor—or find that the arch now leads back to the room it just left.
Misaligned rooms: A chamber may be larger inside than outside, contain a second version of itself, or preserve a view of a place that is no longer physically nearby.

Running the effect

Use the instability to create choices and discoveries, not arbitrary punishment. Give the party a sensory warning—a change in pressure, a distant furnace breath, grit falling upward, or a window showing the wrong sky—before a threshold shifts. Keep at least one route forward visible or recoverable. The Mansions are dangerous because their architecture has become unreliable, not because the GM can erase a character’s progress without warning.