Nothing truly exists - it is all the stuff of dreams, of the imaginary and artificially created. However, to those beings and minds that exist within it, everything is very REAL and it is impossible to tell the difference between outside the Heartstone and inside.

Imagine a whole mirror and then imagine that mirror smashed upon the ground. Each shard of that mirror would reflect much of the same as the whole mirror did, but would also reflect each and every fragment next to it and so on and so, showing reflections going into infinity. This is the way Eldahar's alternate realities works... Eldahar used to have solid alternate realities... but after Orion's breaking of the Heartstone, each reality became a fragmented reflection of itself and the others around it - all called IDS.

These IDS vary in size, shape and integrity. Some IDS represent whole lost civilizations now isolated from other realities and long forgotten. Other IDS represent lost continents, isles or indeed whole imaginary worlds / realities. There are IDS floating in the Heartstone's nether regions that hold ancient secrets whilst there are others that merely parallel or mimic other IDS, following similar timeline's but with subtle differences.

All in all, the Heartstone is like any normal being's imagination - endless. Any number of beings or lands can exist within it and invariably do. Though to date, the most real reality remaining in existence is the World of Eldahar (aka The Prime) the prospect of journeying through the Heartstone's past into the Time of the Titans and the Age of the Dragon Wars can be appealing to some.

Adventures in the IDS
Many people have journeyed from Eldahar into the IDS but not many have returned. After Orion's "cracking" of the Heartstone, Eldahar's IDS became even more fragmented and unstable. Plunged into chaos and torn asunder by the power of Orion's mind, the realities began collapsing and crumbling as the hairline bridges interconnecting them shattered. Navigation through the Ids became impossible as for every one Reality that existed, another thousand sprang up.

In the Campaign of 2600, Adunathel, Ashar, K'Dina, Ankha Khazarad and Goruan Eshan all entered Eldahar's IDS, albeit only briefly. Later in 2617, Ragnek Stormcrow and his companions begin learning more and more about the Ids and what they mean to Eldahar. Then in early 2617, Ragnek enters a mystical cave called Kand's Hollow. Here he unknowingly plunges Eldahar Prime into a Temporal Stasis.

Fundamental Laws of Space, Time and Reality in the IDS.
As IDS are by their very nature, less stable and REAL than for instance the ID that is Eldahar Prime, it stands to reason that the physical, spiritual and magical laws governing them are also less stable. It is possible to enter an ID and suddenly find yourself gifted with magical powers based upon your heightened understanding of reality and how IDS work. It is just as likely that you step into an ID and find yourself suddenly occupying your "twin's" reality / body, living out an alternate life where you chose to go left instead of right etc. If this weren't enough, reality could end up so twisted and different that you arrive on an ID and undergo a complete physical and mental change from male to female, human to elf or dwarf to horse. The possibilities are endless but generally, the further you travel away from a stable anchor like Eldahar Prime (the main world of the Eldar Campaign) the more likely and drastically reality will warp. A lesson to all you ID travelers out there - don't wander too far away from what you know.

The Journey's of Goruan Eshan
In 2601, Goruan Eshan stepped through an ancient Titan created portal and began a journey through the IDS that would eventually lead to his death. Very little is known about his journey but what has been pieced together from various sources is written here as a warning to those who might feel tempted to wander from the straight and narrow path of substance into the stuff of dreams. Yes, Goruan Eshan died... but the ancient relics of extinct civilisations and races maintained his body through magical and artificial means... making him a formidable foe even after his heart stopped.

The Journey of Arden of Elarin
In 2617, Arden, Chosen Mystic of the Order of Seekers, arrives at the Edge of the World and enters Eldahar Prime via the Dream Plane. She meets up with Ragnek Stormcrow (aka Thenox - Overlord of Hell) and Tomorrow (aka The Prince of Planes). Carrying the sword "Heart Seeker," (Fayn Sûl), a piece of Baphomet's spirit frozen in Time and Space, Arden continues her Quest for the One Thought (Baphomet) in the hope of averting a terrible plague that is ravaging her home World.

The Legend of the Prime
Two other important events takes place in 2617 (circa Eldar Prime) and Ragnek Stormcrow is responsible for both of them. 

First he causes a Temporal Shockwave by plunging one of the Daggers of Life into the Sun Crown (see Keys of the Tain). This causes Eldahar Prime to suddenly and abruptly grind to a halt. As the Prime freezes in Time and Space, a tremendous strain is suddenly placed on all the adjacent realities with many experiencing planal collapse or erasure. (The shock of crashing to a halt is like a car hitting a wall at 100 miles per hour.)
Of course such an event does not go unnoticed in the Idiom. Many of the Ancients who dwell beyond the Prime sense it and begin their own investigations; after all, it isn't every day that another Reality directly impacts on your own.

The second major Idiom impacting event of 2617 happens when Ragnek involves himself with Time again. He casually walks into Kand's Hollow, expecting to be immune to its Temporal effects but unknowingly takes several thousand years to walk 85% of the way across the room.

*Note - Kand's Hollow is basically a Temporal trap. It is designed to snare the greedy who will never contemplate in the few seconds they think it will take them to cross the room, the possibility of turning back. Those few seconds become a literal Eternity as the closer the being gets to the stone at the end, the more drawn out Time becomes. Hence, the being can never reach the stone - as the stone exists at the End of Eternity.*

Fortunately for Ragnek, the Crown of Night he wears causes the whole of Eldahar Prime to be snared in the Hollow's Temporal effects. Those Ids closest to the Prime are slowed the most whilst for those furthest away, hundreds of thousands of years pass.

Of course the "Prime" is actually only one half of the Energy that makes up the Idiom. The image above has been proven by the learned scholars of the Idiom as not entirely accurate. Read more on the Animus, Anima, the Prime and the Nexus to understand further.

Yonah - Realm of the Axel.
See Darkstar
 

It isn't long before Felda (Goruan) starts killing Kuzdan left right and centre in an attempt to liberate the Aven and feed Kranatakyn.
Felda discovers that the Kuzdan are mining and converting various Living Crystals into a energy source to fuel their plane jumping technology.
Felda begins a revolution to free the Aven and drive the Kuzdan from Saventia. Kranatakyn casts some powerfully destructive magics.

Kuzdan - dragon men who can breathe cold fire and freeze people to the spot. Stand approximately 7' tall with scaled skin and dragon-like heads.
Felda - one of the Ancient Crystal Kin, a race of androgenous beings that have crystals buried within their chests and can commune with the Living Crystal's of Saventia.
Living Crystals - Come in a variety of colors, each with slightly different functions. Green, Blue, Red, White, Black, Brown, Yellow, Gray, Orange, Violet.