After a long while, one by one, the Gods came to their senses and ceased digging. "Bury me as deep as you can, when my wound takes me," the Creator had said often, "and you'll find my last secret" - but as the first wild pangs of grief died down to become an aching sorrow, the Old Gods lost their stomach for digging, or indeed anything to do with the body, and left. Eventually, only five Gods remained digging.
A week and a day later, they sent a message to the rest of the Gods on the low winds, and the message said this:
"We, the five Last Mourners of the Creator, hereby declare ourselves Lords of the Underworld. The death of the Creator means that in time all living things will die, and yet even then there will be no end. In digging we discovered the last masterpiece of the Creator, the Underworld - and to the Underworld will go the spirits of all dead things, that they need not know the final death. The Tomb of the Creator we have erected at the bottom of the Pit is the entrance to the Underworld, and its Five Lords shall live in the Tomb."
Each Old God was invited, one by one, by the new Court of the Underworld to visit the body of the Creator before it was placed in the Tomb. Then the five Lords placed the body in the Tomb, and erected an Outer Tomb at the entrance to the Pit to serve as a watchtower and a gate, and since then the Lords of the Underworld have been a mystery.
They have never knowingly allowed anything which still lives to even descend the long stairwell to the Inner Tomb, let alone pass through the Inner Tomb and into the Underworld, and they guard their secrets closely, and therefore little is known about what they get up to. The following is what they have seen fit to reveal, and what has been noticed over the years:
They are mercenary beings, dislike showing themselves, are masterful shapeshifters (no match for divine Mimics, however) and have a sadistic sense of humour. They can be summoned and bound to tasks by mortals through the use of complicated magics, all of which require the surrender of a human soul. This isn't necessarily the demonologist's soul, though selling one's own soul to a demon gives one access to much more demonic power and aid. Demons love to trick, cajole, or coerce mortals into giving in to their baser instincts.
It isn't clear what the demons actually do in the Underworld. Their main duty seems to be to guard the entrance to the Outer Tomb, and the stairwell leading down to the Inner Tomb, and the entrance to the Inner Tomb.
The demons are led in war by the Sentinel of the Tomb. This has only happened once, during the Unreal War.
When the Iron Rule came down, the Gods of the Iron Laws sealed the entrance to the Outer Tomb, trapping the High Lord and the surviving Lords of the Underworld inside. In the Iron Reign the souls of the dead were trapped in the ground at the places where they fell - occasionally escaping, leading to mortal tales of haunted places.
During the year-and-a-day in which the Iron Rule fell, the souls of the dead were all released from this imprisonment, and now the world is plagued by wandering ghosts, waiting for the Shepherd to take them to their final rest.
The Lords of the Underworld tend to wear full-face masks, preferably expressionless ones, when they come to social events.