You know you’ve done a good job at bringing a horrifying monster to life when your developer tells you, “Please don’t ever use this in a game I’m playing.”
A feral magical predator, the peryton is known for their predilection for feeding on hearts — and for the fear that instills in characters who fight them even, before the fight begins. They are a creature both old (in game terms) and new (in real-world terms), having been around since the AD&D Monster Manual. But they were sourced not from ancient mythology (as many of the creatures of early D&D were) but from Jorge Luis Borges’ Book of Imaginary Beings, written in 1957.
The peryton’s hunger for hearts has traditionally been mostly flavor, with versions of the creature from AD&D through 5e detailing how a peryton will bite out the heart of a hero only once that hero is dead. But for CORE20, I thought it would fun (for the GM; players’ opinions may vary) to tie the peryton’s heart harvesting to the mechanics for death and dying — allowing the peryton to take a fallen character from dying to dead with fatal speed.
(Click on the stat block header below to download the full stat block in PDF.)