Font of Avernus

The Font of Avernus or Avernal Font is a source of mystical vapors that grants powers to its guardians, the House Avernus. It flows from a crack in the stone, and breathed in by members of the House. The vapors resemble a black mist that absorbs light, and imbues strange powers over life and death. Those attuned to its energies can also see fortunes and fates in the mist, revealing secrets of lordship, war-making, and dominance. For this reason, the powers of the Font are hated even by the immortal demons of hell.

The black mist itself may be sentient, although its motives are unclear. It chooses mortals to defend it, allowing them to forge weapons in the mist. The mist is also capable of conjuring up creatures for its defenders, such as Netherax.

Lord drank deeper than any from the Font, and has since become a supernatural being, a creature of the black mist. Abaddon states that it is the mist that controls him, not the other way around.

Trivia

 * The Font of Avernus is likely based on theories regarding the Oracle of Delphi, whose prophetic visions may have be caused by inhaling natural gases seeping through the ground.
 * Avernus is a volcanic crater, believed by the Romans to be the entrance to the underworld.