Poltergeists (as they are called in Prima's Official Blood Omen 2 Strategy Guide) appeared in Blood Omen 2, but only in one specific location. They could be found in a section of the Eternal Prison; in an area where a central mechanism caused numerous quarter-circle platforms to rise into the air.
As Kain travelled across these platforms and jumped between them, the Poltergeists would materialize out of nowhere to fight him. Annoyingly, they were quite resilient, but had very little blood and Lore. Considering that they were ghosts - or, at the very least, ghost-like creatures - this was to be expected, although it was unhelpful. They stopped glowing when they were defeated.
It appeared that these 'noisy ghosts' - the literal meaning of the word 'poltergeist' - were not human spirits, as they had horns protruding from their skulls. The origin of these floating skeletal torsos was ultimately unknown.
- Blood Omen 2: Prima's Official Strategy Guide (ISBN 0761537740)