Dullahan

Dullahan, the Cursed Revenant

Lore:
Many millennia ago, when the world was plagued by elder beings of great malevolence and power, a group of ancient magi sealed the cthonic monsters away, burying them deep beneath the earth and sending them into a state between life and death. One such being was M'Nagalah, a horrible one-eyed creature that spread rot and pestilence wherever it roamed. Its final act as it was cast deep beneath a swamp was to desolate the region, forming the infamous Grave Marsh. M'Nagalah stayed dormant until the unexpected efforts of a group of Elven druids to revitalize the swamp awakened it. Conscious once more, but unable to escape its prison, it corrupted the druids and sent forth a malevolent spirit - Dullahan - to act as its herald. Dullahan required a vessel to act in the physical world, and quickly found the corpse of an armored soldier. Discarding the ancient bones, Dullahan haunted the suit of armor and departed to gather forces for its master.