Colossal Guardian — the pet, avatar, and warden of Mollthain, the Rampart
Mollthain's Warden is the ancient monster set in the depths beneath Grithmaar Deep by the departed god Mollthain, the Rampart, to steward a local light. It is the "great creature left by Mollthain" that Ygva directed the party to seek — a being that holds or embodies Mollthain's essence, whose power she hopes to harvest for the god-pillars of her great pyre. It is the same monster Jamal's people once broke into and, out of sheer terror, dug away from rather than face; the party believes it tied to the ruin of Grithmaar Deep and Jamal's home.
The Warden is a colossal guardian roughly the size of a five-story structure, radiating overwhelming Splendor — the magic of the gods. It is impervious to fireball, and can raise crystalline walls to bar and reshape a battlefield. In the assault upon it, it wept molten streams and threw up protective barriers, igniting under sustained attack, and it rejected every demand to stand down, its refusal shaking the chamber.
It was first glimpsed through Sylvie's Umbral Raven, sent to scout the corridors below Grithmaar Deep amid assembled enemies. The Warden detected the raven and tore its essence apart, annihilating it; Jamal recognized the described being as the ancient monster the party had come to confront.
When Sylvie reached out magically to Ygva in a dream, Ygva offered methods for taking the Warden's power: destroy it and take its remains, rebuild or transform it into a vessel, or siphon its essence into a suitable container — to which end the party intends to channel captured Splendor into the Living Fortress.
Not to be confused with the Guardian — the purple, multi-eyed feline demon that guarded the Sacred Tree and was destroyed in the Woodland — an entirely separate creature.