A noxious agent brewed by the warriors of Xanthe, distilled from whole serpents, excrement, and deadly herbs reduced over a number of days in boiling cauldron.
Weapons treated with Xanthicon deal an exploding d4 (4s are rerolled and summed) poison damage. Any creature which has taken more than HD + Constitution modifier damage from Xanthicon in a single day begins to have trouble breathing. Every strenuous action they take incurs a DC 14 constitution save or suffer a level of exhaustion.