Husks are physical manifestations of the souls of the damned. The physical form is based on the value of the original soul, which is determined by the strength of its will and its prevalence in public consciousness: the living souls that remember it. Filth are the lowest form of Husk, whose souls were too weak and unimportant to even form a complete physical body. Even among Husks, they have the lowest intelligence, driven purely by hunger.