The Deeplands and the Feywilds

Within the Elsewhere flows the Fey Wilds, and the Deeplands, two planes which harbor chaotic energies that cancel and balance each other out. Neither the Fey Wilds nor the Deeplands can exist without the other one, and are deeply intertwined, their geography constantly shifting. One can, without the proper wayfaring, accidentally walk straight into the Deeplands from the Wilds and vice versa. Both the Fey Wilds and the Deeplands are also both closest to Malkor, and so fey and shadow creatures appear in the realm of mortals far more often than any other extraplanar being. There are also several direct gates to these planes from the mortal realm, and there also exist a few backdoors to each realm, with the exception of Asakar and Norgoth, through these planes.
Each of the two realms have their own god, Amaranthie for the Fey Wilds, and Loketh for the Shadowlands. Each is a guardian of each existence, and both were appointed by Odari himself, though they are both Chaotic in nature. Loketh and Amaranthie are the only non-Lawful gods that are permitted into Asakar, though neither of them rarely spend time there.
Scholars and researchers of many kinds speculate that both of these lands are essential to Malkor having magic, though they aren't sure just how it's intertwined. The truth is complex, difficult to explain to a mortal mind, and requires the viewpoint of a deity to fully grasp.
As individuals die, their lingering inherent prana evaporates and shifts into the Elsewhere, and generates Anima; Seeds that spread through the Wilds and the Lands. The dead nourish and give life to the lands, and in return new prana spills into and infuses Malkor itself with it, thanks to the life that the anima generates in the Elsewhere.
Often, anima seeds in the Wilds tend to generate more plantlife, whereas the Shadowlands have their seeds birth different sorts of animals and critters of various size and properties. A few are common to summon as familiars. These mirror existences of creatures and plants on Malkor (though not to a precise level), and often, when the Malkor original dies, the Elsewhere mirror dissipates, switching places with the anima and the prana. There is a form of ecosystem there, and without it, Malkor would be unable to create new life.
Because the Wilds and the Lands stretch across the entirety of the Elsewhere web, and act as a method of traveling across realms, each realm is in a way connected. This fundamentally changed how the realms interact with each other, into the present day functions and methods. Previously these interactions happened only on Norgoth, and the nine realms looked vastly different. But thus was as far back as during the age of the Primordials.