The Shard of Resentment

As the Negative Plane collapsed into Elemental Chaos, a planet known as Resentment was consumed by planar rifts. The rifts phased pieces of the planet between the Prime and Negative Material planes until the collapse of the Negative Plane settled and Resentment was left divided, partially formed in the Material Plane and part in an unstable pocket plane. The wraiths left by the original inhabitants, all of whom died as the rifts tore the world apart, called the new world "The Remainder".   Beyond the edge of the Remainder, beyond the Great Cataract, lies the pocket plane and the Shard, which continue to phase between worlds, capturing formations and creatures and pulling them into the Remainder (or depositing them *from* the Shard). Countless lifeforms from dozens of planets would populate the Remainder in the millennia after the Phasing.   For nearly four thousand years, this hybridization has marched on as more and more alien species found themselves suddenly transported to the Remainder by the whims of the planes.