I can find no lore to show why Shadar-kai would find them-self in Ebron/Mabar. What do you think, ya or nay?
This is what i have found so far.
Devs, any comment or referents would be great as to why.
Mabar the Endless Night is a blackened realm where the faintest spark of light is quickly devoured by the unending darkness. It is a plane suffused with negative energy and the antithesis of Irian. Negative energy spells are maximized and all the inhabitants of this plane are immune to effects from negative energy. Positive energy spells are impeded here.
The nights grow blacker and more dangerous when Mabar becomes coterminous with Eberron. Travel to Mabar becomes as easy as stepping into an area where there is no light, and inhabitants of the plane slip out from the shadows and into the world. The plane becomes coterminous on three dark nights in the dead of night on the nights of the new moon closest to the winter solstice.
Consequently when Mabar is remote the darkness seems to sap from Eberron. These periods occur every five years on the nights of the full moon around the summer solstice.
The shadar-kai, or shadow fey, are a race of bitter, determined folk whose souls are poisoned by shadow. Grayskinned and dark-eyed, the slender shadar-kai stand slightly taller than average humans, and their soft movements exude grace and uncanny stealth. Shadow follows the shadar-kai wherever they go. Shadows cast by the folds of their clothing seem deeper than those on humanoids, and a shadar-kai can seemingly fade out of sight by simply stepping into any common shadow. The shadar-kai prefer light weapons suited for grace and agility, especially spiked chains. Many shadar-kai favor a variety of piercings and tattoos.
Long ago, the shadar-kai thought to preserve the world from the rising humanoid races. Skilled in shadow magic, the shadar-kai made a pact with a dark power of the Plane of Shadow to cast the world into an endless twilight in which the shadow fey would rule supreme. But the experiment went awry, and the shadar-kai were left bound to the Plane of Shadow, cursed to lose their souls in its dark depths. This shadow curse affects shadar-kai to this day, and every member of the race is engaged in a lifelong struggle to stave off inevitable doom.
The continuous pull of the Plane of Shadow has left the shadar-kai grim and embattled. Few races understand the plight of the shadow fey. Even the temporary solutions the shadar-kai have found leave them struggling with constant pain, making them vicious. Their willingness to commit acts of cruelty and violence has increased with each generation.