Shemhazian - Gargantuan Fiend (CR 20)

Don't be fooled by its vaguely puppy dog like face, the Shemhazian, a daemon from the Pathfinder game is a certified abyssal badass that will seriously ruin your day if you are not careful. A vast, highly perceptive daemon, it is often used as a guardian by abyssal lords and is prized for it formidable powers and might.

Who's a good boy then? Whooooo's a good boy? You is! You is!
There are rituals that can summon and bind these daemons, and their names are prized secrets amongst many orders of magi. A Shemhazian is said to guard each entrance into the House of Presences in ancient Pentas Demonica, the City of Stained Stones, presenting a deadly threat to those that would seek to plunder its evil secrets, and there are stories of these creatures wandering the world post Sundering, seeking every being that currently, or who may one day, know their true names.