Fallen former commander of Cassan's Keep
Sir Keegan is (now) essentially a skeleton in plate armor, though his movements are surer than most skeletons, and he he retains at least a semblence of his mind.
Sir Keegan is currently a suffering soul residing forever in his crypt in the Keep. Over two hundred years ago, as Comamnder of Cassan’s Keep, he fell under the foul influence of the rift deep in the earth, and slaughtered his family and many of the men under his command. Eventually he was driven into a crypt and sealed there by the remnants of his force, who then abandoned the Keep as cursed. Sir Keegan has been there ever since, tormented by the knowledge of his heinous crimes.
To aid the Downies in their quest against Kalarel he gifted the party with his magical longsword Aecris, in the hopes that at least the blade might be redeemed if if he could not be.