This power allows you to draw upon the primordial power of the pit. You gain +5% poison immunity and +10% poison armour at rank 1, +4% and +8% at rank 2, +3% and +6% at rank 3, +2% and +4% at rank 4, and +1% and +2% for every rank after 4. You also gain +1 poison bypass and +1 auto-absorb per rank.
If you also have Black Dragon Descendant, the above bonuses are all doubled, and you get an additional +2 Attack/Ascendancy and +2 Damage/Power to both your physical and magical acid breath attacks while in Dragon Form.
At rank 10, this power unlocks the Gas Wave spell sigil, with more powerful versions available at rank 20, 30 and 40.