Deathweed

Deathweed was a poison reagent used by rogues to create a nature damage poisons and healing reduction poisons.

Source
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As an ingredient
Deathweed was used in the following recipes:

Poisons

 * Anesthetic Poison (I)
 * Deadly Poison (I, II, III, IV, V, VII)
 * Wound Poison (I, II, III, IV, V)