Grim

A grim is a warden tied to a single site and sworn to keep evil out of it. It never leaves, even after its charge has crumbled into ruin. Each night it takes one of three shapes, a black owl, a massive black hound, or a huge cat, and must hold that form until dawn, when it turns ethereal until dusk and may choose again. The dog form is most common and the cat least. In the hidden shadow realm, where morning never arrives, a grim is locked into whatever form it last chose.

As a dog it bites each round for 2d8. As an owl it swoops at the eyes, raking with two talons for 2d4 each and pecking for 1d4+1. As a cat it claws for 1d2 twice and bites for 1d4, and if both forepaws strike it rakes with its hind claws for 1d3 each.

Every grim turns undead as a 9th-level cleric, with +2 against evil extraplanar beings, and only +1 or better magical weapons harm it. A 10-foot protection from evil aura surrounds it, and it detects evil within 70 feet even through magical disguise, so evil creatures never surprise it. Its half-ethereal body and keen senses double its own chance to surprise. When it senses evil coming, it lets out a deep, ghostly howl, and any evil being within earshot makes a morale check every round or runs.

A grim is a loner that acts only in service of its duty. Most visitors never know it is present; good folk are ignored, though it warns of danger and joins any fight against trespassing evil. Where the sun rises, it fades and becomes intangible by day, reappearing at sunset fully healed. The magic that once called and bound grims is lost, and most now guard forgotten ruins. None watch over inhabited places, perhaps because crowds weaken the binding.

The grim neither eats nor sleeps and exists only for its endless watch. Heroes may find it an unexpected ally, but it deals with others only when they cross the rules that bind it.