Ipacia, the Realm of Stars

Credits to Gioele Muscolino for the awesome cover art!

First to be created by Yamma and Alindr, Ipacia is the Realm of Stars — the great cosmic ocean within which strange formations, stars, and the planes themselves float. It is a sea of opalescent gasses, threads of gossamer starstuff, and the many structures hidden within both. Ipacia is simultaneously infinite and finite, understood and mysterious. It has regions which make sense geographically. The closer one gets to Gliziarial, for example, they will find themselves amidst titanic mountains and rock formations floating amidst clouds of silver. Yet, these mountains have no bases nor peaks, and the region they inhabit has no definite boundaries. One could exit the Realm of Malachite and travel through this mountainous portion of Ipacia for a few minutes or for weeks, with the difference seemingly being a cosmological coin toss.

Inhabitants

On account of its incredibly diverse regions and unbelievably vast size, Ipacia has a great many unique species. It is the Realm of Stars that the war-torn, spacefaring species of the gith roam. A variety of predators, from the great dreadnoughts of legend to smaller, more agile creatures of psionic capabilty, call Ipacia home as well.
After the Reshaping, Ipacia was a chaotic place criss-crossed by paths between the planes. Since the Reckoning, the Realm of Stars has become a land of lawless conflict and piracy. With planar travel all but dead, the warrior race of githyanki slaughter those stragglers and wanderers unfortunate enough to be found, while the githzerai protect what few bastions they can, both races doomed to continue the conflict begun when they were divided and pitted against one another in the God-Wars.
Beyond the conflict of the gith, the aforementioned predators stalk unseen from the infinite hidden vantage points afforded to those with the ability to travel through the Realm of Stars. And more than even those varied creatures, countless other entities call Ipacia home — be they intruding forces from Xeccamund, ancient dragons hidden among the stars, various displaced planar inhabitants, or countless other types of creatures. Ipacia is the cosmic ocean upon which the planes are mere islands. All creatures pass through it, in life or in death.

Travel

Depending on the method of travel, Ipacia can be the easiest or most difficult realm to reach. All forms of planar travel technically pass through the Realm of Stars — be it teleportation magic or advanced starsailing ships — but it takes luck, specific magic, or a mix of both to stay in Ipacia.
Beyond even reaching Ipacia, moving within the realm is something else entirely. It isn’t bound by the normal rules of reality that most other planes are beholden to. Up and down aren’t even subjective — they just don’t exist. Gravity has no uniform hold on the different locales in Ipacia. Sometimes, even the massive mountains near Gliziarial have no gravitiational hold, while the smallest pebbles will attract enough matter to grow into city-sized boulders.
To move through the Realm of Stars, one needs either psionic capability or spatial magics. With one or more of those abilities in hand, creatures can do unbelievable feats in Ipacia: construct entire structures with their mind, blink through time and space, and more. The most common way to travel without those abilities is an act known as Ipacian navigation: by using specifically designed vessels, one can actually sail the Realm of Stars. But, it is dangerous, hard-to-achieve, and vessels capable of Ipacian navigation are uncommon. And without any of those, an ill-equipped traveller — or an unfortunate soul who stumbled through a planar portal — is dead in the water of the stars.

Type

Dimensional plane