Cosmic realignment

The ruins of Darkspine, and four older ruins of gate-towns

Cosmic realignment is a process by which, if a location on the Outer Planes begins to embody the nature of a different plane too closely, the location, and its inhabitants, will shift to the target plane. For some inhabitants, this is desirable; other elements try to prevent it from occurring.

This phenomenon is most often witnessed with the Gate-towns, 16 locations around the Outlands built around a permanent portal to one of the other Outer Planes on the Great Road.

Known Instances

In Ribcage, the gate-town to Baator, if one travels through the gate, they'll find themselves in the ruins of Darkspine on Avernus, the first layer. Darkspine was the previous gate-town to Baator; once it arrived, it was attacked by fiends and blasted by fireballs common to Avernus. A few survivors eke out a living, but it's largely abandoned.

Even though each plane is infinite in scope, cosmic realignment does pull territory with it; each gate-town pulled over adds to the space on the shore of the River Styx. Accordingly, as you travel from Darkspine to the Styx, you will pass through the ruins of four other previous gate-towns, each older and more destroyed than the last.

In 125 YFHR, Trias the Betrayer, a corrupted deva, enacted a campaign of fear and violence in the gate-town of Curst, causing it to slide into Carceri. After performing a number of good deeds and defeating Trias, The Nameless One and his cohorts managed to reverse the realignment, returning Curst to the Outlands.

In 127 YFHR, the gate-town of Fortitude was preparing for an event they called the Harmonious Ascension, a purposeful cosmic realignment to bring them to Arcadia. The pit-fiend Zaggutch, operating on orders from Dispater himself, enacted a plan to hijack the ceremony mid-realignment by committing evil acts in order to, instead, bring Fortitude to Baator, but the plan failed.

Faunel has recently crossed over into the Beastlands, leaving settlers to build a new Faunel in its place.

Effects

Several effects of the process of cosmic have been noted, but it's not certain if they're universal or specific to certain locations.

• During the process of realignment, the gate grows in size until it engulfs the city. Fortitude's gate of green flame grew in height until the sky surrounding the city walls was all green flame.
• Darkspine was notably a different city from Ribcage, although it's possible that it had previously been called Ribcage and was only renamed after realignment occurred. In other cases (Fortitude, Faunel), the replacement city has the same name as the old.
• From the perspective of those in town, the gate may appear to travel to the other plane with them, but they're seeing the "other side" of the gate. Traveling through a gate-town's gate takes you to the previous incarnation of that town on the other plane (e.g. Darkspine), although the state of that location may vary. Thus each Outer Plane has their own corresponding gate-town (or ruins thereof) leading back to the Outlands.
• In some cases, cosmic realignment leaves almost nothing behind, except the gate (Curst, Faunel). However, when Fortitude crosses over, another copy of the city appears, containing similar buildings but different residents.