The Negative Quasielemental Planes (TIP)

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Just as there are quasiplanes fueled by the power of the Positive Energy Plane, so too are there regions dominated by the darkness of its opposite, the plane of Negative Energy. Markedly different than their positive counterparts, these are generally grim places that break down matter. Undead are common in these quasiplanes, tortured spirits invigorated by the negative energy that infuses everything.
ASH. The quasiplane of Ash is an accumulation of burnt matter pressed into a solid mass. In most areas, the quasiplane has the consistency of hard-packed soil, though some regions are much less dense. This place is born of the union between Fire and the life-draining power of Negative Energy.
Those who travel to the quasiplane of Ash find it an amazingly inhospitable place. Its very nature is such that it siphons the heat from all living (and unliving) things.
DUST. When Earth is infused with Negative Energy, it breaks down and forms the Quasielemental Plane of Dust. Unlike Ash or Earth, Dust isn't a solid mass. Instead, it's an expanse of tenuous atmosphere filled with swirling particles of granular matter.
The greatest threat a body faces from the quasiplane of Dust is disintegration. Eventually, even the most powerful basher will be taken apart. Little can be done to resist this effect, which extends even to portals and gates that lead here.
SALT. There are few who'd argue that water is not the lifeblood of the multiverse. But even so vital a fluid can be stripped of its nurturing value by the influence of the Negative Energy Plane. This is exactly the process that has spawned the quasiplane of Salt.
Here, in an endless world of crystalline structures, a visitor can expect to have the moisture drained right out of his body. Not long after reaching the quasiplane, he'll become parched and thirsty. In the end, even the toughest planewalker will collapse and be consumed by Salt. When that happens, all that's left is a withered corpse that looks as if it'd been mummified a thousand years before.
VACUUM. The quasiplane of Vacuum is a region of utter nothingness. Formed at the junction of Air and Negative Energy, it has no light and very little matter. Few creatures can endure such surroundings. 
'Course, those who do manage to survive in Vacuum are bound to be tough. That means that any cutter with a mind to travel to the quasiplane should plan to stay on the good side of the inhabitants. There's no sense in making all manner of magical preparations against the deadly nature of Vacuum only to be sent to the dead-book by an angry native.