Erhard
the waxy man with the iron skeleton and a ruby for a heart
Inside the sealed sarcophagus of Erhard's Tomb — flanked by two unlit torches, in a chamber where the floor is covered in drifting fog — lies "a man's odorless corpse in near perfect condition, wearing fine silk clothes."
"The skin is waxy, malleable like dough and very flammable. Digging into the body reveals an iron skeleton, a fist-sized ruby inside the ribcage."
Erhard is named only by his tomb. He gives no orders, makes no demands, says nothing. He simply lies where someone placed him with great care: a body that should not still be a body, in a cemetery that should not still be a cemetery.
Opening the sarcophagus is a Strength DR18 test, reduced by 2 for each assistant. Failure means everyone involved takes d4 damage as the lid falls open.
Graven-Tosk, Erhard's Tomb, Graves Left Wanting, The Plague Pit (adjacent — west ruin-tunnel)
Everything. Who Erhard was, why he was prepared this way, why his skeleton is iron, why the heart-cavity holds a ruby, who sealed him, who keeps the torches unlit, are all canonical gaps. The waxy and flammable skin invites a single grim experiment. The iron skeleton is mechanically unique — no other corpse in Mörk Borg has one, and what an iron skeleton means for a soul's passage is unstated.