Throughout the Multiverse, there are tales of beings that act as the living force of their plane, such as Gaea on Dominaria or Progenitus on Alara. The idea that the planes are alive is far from unique. What is unique, however, is that Iun Ilana is quite willing and capable of proving itself -- or rather, herself -- alive and intelligent.

The Lands and Peoples of Iun Ilana
Iun Ilana is a smallish plane. Her usual landmass is significantly larger than the known provinces of Innistrad, perhaps somewhat in line with the Jamurran continent, and covers around 50% of her surface. The landmass is usually spread across two continents, though as Iun Ilana has a good deal of control over her surface, the shallow strait between their usual positions is sometimes raised to form a land bridge.

The exact outlay of Iun Ilana defies mapping in certain regions. She largely keeps densely populated areas stable, but the wolds are free for her to move, reshaping the terrain as a person might stretch or exercise -- constantly, but intermittently. The larger of the two continents, the Northern Continent, is home to the Head. the Head is a large, lone mountain in the center of a great plain. The southern face is quite literally a face, though how the formation is perceived seems to be somewhat subjective: a female face of the viewer's own species is the most typical manifestation. The Head is the center of a psychic field of phenomenal power -- Iun Ilana can speak directly to any creature with a mind, provided it is within sight of the Head. Many cultures consider pilgrimage there a holy rite, but none have settled around it, as the constant psychic presence is not something most individuals can stand on the scale of months or years.

The stable, settled lands of Iun Ilana include...
The Locks: The locks are a formation of mountain chains with forested valleys running between them, along the northeast of the north continent, so named for an appearance resembling on some representations of the stable world, flowing locks of hair. The Locks are the least 'settled' region that isn't prone to topographical upheaval, seeing as its residents, while numerous, are semi-nomadic. The population of the Locks consists largely of elves in the lower lands and humans that tend to stay higher on the slopes. The elves of the Locks, the only elves upon Iun Ilana, are slighter than average humans. Their skin tends to be a rich, earthy red-brown and their hair dark brown or black. The humans of the Locks are tall, well built, and have pale skin and eyes.
Blazing Steppes: Windswept lands as close as any dare make permanent homes to the Head, the Blazing Steppes are home to the more major human population of the north continent. They build their homes of mud brick and practice farming and animal husbandry as their main industries. The tall grasses of the Blazing Steppes are often prey to wildfire, earning the land its name, but the people set even more fires believing that the ashes of even a controlled burn of wild grass will make a good offering to Iun Ilana for the fertility of their fields and the luck of their people. If this is not so, she has not dissuaded them from this practice. Blazing Steppes humans are less powerfully built on average than those of the Locks, but are also fair of hair, skin, and eyes.
The Great Reef: The Great Reef exists off the southwestern coast of the northern continent, and is home to the heart of the merfolk civilization of Iun Ilana. They shape their structures out of coral, which can be induced to grow quickly as is needed with magical prodding. The sea here is very shallow, as the merfolk enjoy it, in some areas less than ten feet deep for miles around. It is a place full of color and life. The merfolk themselves are of an interesting sort: they have the upper bodies of humanoids (mostly like humans, though their skin is more pallid and their hair, only ever upon their heads, can come in a number of colors not found among humans), while their lower bodies are more like the tails of sea snakes than fish, to the point where they are capable of slithering on land, even holding their torsos upright. The merfolk of Iun Ilana breathe air, like dolphins or whales, though like cetaceans they can hold their breaths for fantastic lengths of time compared to land-dwelling races.
Cemetery Mire: Once, Iun Ilana was home to another civilization, but a catastrophe that came from beyond the plane forced Iun Ilana to react to save herself, unfortunatley killing most if not all of the members of that civilization. Cemetery Mire the remains of the First Peoples of Iun Ilana, and most particularly the Giants, who were a race born of unions between humanoid avatars of Iun Ilana and mortal men. These peoples have been given a second chance at half a life by their mother-creator. Most are quite, peaceful, and as much as they have emotions happy to still exist rather than having died a final death. Not all the undead of Cemetery Mire are of the Old Civilization -- some humans, and rarely members of other sapient races (elves, goblins, even merfolk) that fear death above all else have trekked there in the hopes of being reanimated, seeing as anything that dies in the mire can be reborn as undead (including wildlife, but more often sapients.) The majority, however, are ancient dead. Their leaders are a council of thirteen ancient liches (Nine giants and four others), whose memory of past days is the best preserved and whose magical talents are without external peer.
The Womb: A large basin in the southern continent seen as the cradle of the modern human civilization. the Womb is a broad, flat expanse with many cities of high, stone structures and vast fields. It is separated into three kingdoms united under an emperor. In the past, the wars and struggles for control of the high throne have been bitter and fierce. The humans who live in and around the Womb have tanned skin and tend towards dark hair and eyes.
The Glittering Peaks: The Glittering Peaks, deep in the southern continent, are home to the goblins. Goblins of Iun Ilana see wonder in all things through their faceted, gem-like eyes. Knowing their homeland, it is easy to understand why: the glittering peaks are marbled with veins of iron pyrite in places, sometimes looking like waterfalls of gold. In others, crystals as large as a house can jut from the rocks, while elsewhere you can discover canyons of iridescent mica. The entire landscape shines, in countless different ways. The goblins themselves have a brown-grey skin that is much like flint stone -- indeed, they can create small sparks by clapping their hands against each other (and some duller-witted examples of their kind find hours of entertainment at a time in doing just that)

The Manifestations of Iun Ilana
Iun Ilana is not merely limited to speaking from the Head -- she can manifest avatars anywhere on her surface. The avatars seem to always be female and can be of any species, though no matter their form they seem blessed with communication regardless of language. When Iun Ilana wishes to be heard, it is impossible to deny her presence, radiating magical power regardless of her shape -- wren or baloth, mermaid or human, all are equally great and terrible -- but sometimes she conceals her might, seeming to enjoy living as a part of her 'children' for a brief time, hours or days before revealing the ruse or simply vanishing.

Iun Ilana is a strange being in some ways. She is ancient, and carries with her the wisdom of such unfathomable age, but much like a child she is full of wonder at nearly every little thing. She is at once painfully aware of the nasty things her ‘children’, the sapient races of the plane, do to one another, and eternally convinced that they have a basic goodness and act brutally only out of ignorance. She declines to interfere, most of the time, in the squabbles of nations, but many are the tales of her openly or secretly easing the struggles of individuals

Wurms and Dragons
Long ago, Wurms arrived on Iun Ilana, quite likely from some other plane. They are potentially gigantic, slimy burrowers that consume rock and flesh alike. Their tunneling causes Iun Ilana great pain, and shortly after they first appeared in massive numbers, even threatened Iun Ilana's very life. Iun Ilana killed most of the worms with a massive tectonic upheaval, crushing them in their tunnels and raining fire down upon those on the surface, but doing so also eradicated most of the other life on her surface, particularly the sapient races of those days. The wurms, however, were not rendered completley extinct, and continue to plague her into the modern day, though hunted endlessly by angels, avatars, and devoted sapients.

Wurms appear to be the larval form of dragons, for wurms that escape long enough (or grow large enough) will cocoon themselves, and dragons hatch forth after a time. Dragons are mighty, winged, fire-breathing monstrosities. They are not sapient, though they act with a malice towards life other than wurms and dragons that would make one think they were. Their priorities are killing anything that moves, eating (either their kills or, as in their larval state, stone), and laying eggs. Even one dragon can deposit many clutches of eggs, to the point where it is almost impossible to eradicate all of them, so presumably they reproduce asexually. Thankfully, enough wurms are killed and eggs destroyed that dragons are very rare, and the number of wurms has stayed roughly stable since Iun Ilana purged her surface.