There is a Legacy version here.

Void

Source Player Core pg. 463 2.0
Effects with this trait heal undead creatures with void energy, deal void damage to living creatures, or manipulate void energy.

Planes with this trait are vast, empty reaches that suck the life from the living. They tend to be lonely, haunted planes, drained of color and filled with winds carrying the moans of the dead At the end of each round, a living creature takes at least minor void environmental damage. In the strongest areas of a void plane, they could take moderate or even major void damage at the end of each round. This damage has the death trait, and if a living creature is reduced to 0 Hit Points by this void damage and killed, it crumbles into ash and can become a wraith (see Monster Core).