Undead monsters similar to ghouls but smarter and more powerful, surrounded by an overwhelming stench

Ghasts look and fight almost exactly like ghouls, but they are smarter and just a bit more powerful. Refer to the previous paragraphs for information about their claw attacks and other abilities. The stink of death and corruption surrounding these creatures is overwhelming. Living creatures within 10 feet must succeed on a save vs. Poison or be sickened for 2d6 rounds (-2 to attack rolls). A creature that successfully saves cannot be affected again by the same ghast's stench for 24 hours. A neutralize poison spell removes the effect from a sickened creature. They may be Turned by Clerics using the same column as the ghoul, but as they are superior to ghouls, in a mixed group of ghasts and ghouls the GM should apply Turning effects to the ordinary ghouls first. Humanoids bitten by ghasts may be infected with ghast fever. Each time a humanoid is bitten, there is a 10% chance of the infection being passed. The afflicted humanoid is allowed to save vs. Death Ray; if the save is failed, the humanoid dies within a day. An afflicted humanoid who dies of ghast fever rises as a ghast at the next midnight, in a similar fashion to the ghoul. However, a humanoid who becomes a ghast in this

Undead monsters similar to ghouls but smarter and more powerful, surrounded by an overwhelming stench

These terrible creatures are more powerful versions of ghouls, and are indistinguishable from them save their terrible stench, released when engaged in melee, that requires a save vs poison to avoid a terrible retching and -2 to all actions, including hit and damage. They can ignore protection from evil unless it is combined with certain pure non-alloyed metals. Ghasts share the same spell immunities that ghouls do, and can travel the dream-realms as well, except in addition to using them to traverse the prime material, they can also enter the lower planes. Certain entities of the higher hells use ghasts as slaves.