Kythri, known as the Churning Chaos, is the conceptual counterpart to Daanvi. It is a plane of chaos, and has a similar (and opposing) underlying rhythm to it. Whereas Daanvi encourages conformity and rhythm, the underlying beat of Kythri is discordant and makes it difficult to maintain an actual rhythm, with all creatures subconsciously avoiding repetition.
Kythri is highly fluid, it's shape and form fluctuating wildly. It is a plane of chaos and change, and the environment within it reflects this. In the Sea of Chaos, landmasses form spontaneously only to collapse moments later, but in other areas of the plane it is more stable, albeit still morphic. There are "islands" in the Sea of Chaos which maintain a consistent presence, even if their exact shapes change. A desert island might become a jungle over the course of hours, but the land is stable enough for creatures to live on it if they can adapt to the constantly shifting environment.
This seems to have some overlap with Xoriat, which itself also seems to embody chaos, but Xoriat is more about the unnatural, and the chaos in Kythri is usually mostly natural forces. A desert might change into a jungle over a few hours, but it's still recognizably a natural desert and the end result is a natural jungle, whereas the environment in Xoriat is entirely unpredictable.
Kythri is always in flux, and nothing stays the same for long. The plane itself abhors repetition, and it is difficult for creatures in Kythri to do the same thing twice in succession. So chaotic is Kythri that spells that attempt to divine information often fail, you can't predict the future in a place where the future is entirely uncertain. Whereas Daanvi seems to resist random chance and events gradually move towards a predictable center, Kythri amplifies randomness and pushes things towards the unknowable extremes. Nothing stays the same in Kythri, and the passage of time is similarly inconsistent, though it still passes forward, unlike in Xoriat.
The native creatures of Kythri reflect the nature of the plane, and are as chaotic as their surroundings. Animals can survive in the shifting islands because they are as changeable as their surroundings, and it's not uncommon to see creatures in Kythri that appear to be chimera composed of several other natural creatures whose adaptations better allow the creatures to survive. Again, this seems to overlap with Xoriat, but these chimera are composed of natural creatures. It's believed that some of the more exotic animals that exist in Eberron, such as griffons and hypogriff's, originally evolved in Kythri and then migrated into Eberron via coterminous periods.
Kythri does not have native celestials or fiends, the native immortals of Kythri are the Slaadi. Unlike immortals of other planes, Slaadi can reproduce and die, but their population remains constant. If a new Slaad is created, an existing one dies (seemingly at random), and vice versa. These slaadi form the only native civilisation in Kythri, and whilst their physical forms can be categorized, their civilisation and system of governence is constantly changing. These changes in their society happen quickly, but not instantly, and in any given Slaadi society there is likely an active revolution happening right now.
Another populous group of creatures that reside in Kythri are the Gith, though they aren't native to the plane. The Gith use their powerful psionic powers to impose order upon the chaos of Kythri, and live in great city-ships that travel through the Sea of Chaos.