From publisher blurb: The endless caves of subterranean Aventyr echo with the cries of the dying and sometimes, during a brief rest by the soon-to-die, the cacophonous symphony of the ahool. Chief among these true predators of the Underworld are the ironsingers, masters of sonic energy that employ their aural abilities to terrifying effect against their foes, but even their lesser kin (the ahooling) incite fear across Aventyr. What do the ahool bring forth from Aventyr? A brand new player race—the ahooling! The fledgling ahool, a monster class (and archetypes!) to stoke the primal fires of these subterranean terrors, evolving them into fully grown ahool! Extensive favored class options for ahooling! New mundane gear! Innovative wondrous items! Never before seen spells! New feats for ahooling to make them true horrors of the Underworld!