The Witcher Bestiary - Alghoul
Alghoul Occurrence: Alghouls appear in old necropolises and crypts.

Immunity: Immune to common poisons and resistant to knockdown attempts.

Susceptibility: Sensitive to silver; the Strong Style is most efficient against alghouls; experienced witchers use the Group Style while fighting multiple ghouls.

Tactics: Alghouls try to knock down their victims and eat them alive.

Alchemy: Cadaverine, white vinegar, and alghoul marrow.

Alghouls are ghouls which had been devouring corpses for so many years that human flesh becomes irresistible and they begin to prey on the living. They are seen in crypts and on battlefields, frequently surrounded by ghouls. Simple folk do not notice the differences between these two types of scavengers - unlike witchers, who know that the alghoul is a more aggressive and challenging opponent.