Taint provides a means of giving characters and/or players a close-up look at what Humanity means for the group. "What does 0 Humanity do?" they may ask. Taint can show them without being permanent.

Secondary effects (as the book says, physical/mental malformations) depend on how 0 Humanity is handled in the group. The nice thing about Taint is that, even using the default, intentionally vague '0 Humanity' rules in the main book, the player gets the character back. [1]