During the Age of Dominance (0-300) ancient armies of outsiders fought across Avergene. This time before the truce was full of caustic battles. Fort Grimstone was home to one such army and to a great and deadly battle.
The name of Fort Grimstone is now mostly lost to history. Eraced in the memories along with the lore of the ancient battles.
Local history maintained by the followers of Bane say that a great host of Bane had camped where Mount Hublia now stands. The camp was huge. The host of Bane was thousands with armies of humanoid slaves, a host of lessor demons, devils, and other out worlders.
The legend has it that a volcano was summoned upon the fort. The flowing rivers of lava moved by the powerful elemental magics buried all within. The fort was lost as the mountain errupted. Yet some were reported to have survived preserved and may still remain trapped in the mountain. What manner of evil remains protected in the solid rock after so many years, one can only conjecture at.
In recent history some have ventured to travel there to find what they can. Only, none have returned. The tunnels and excavations they have started remain. The mountain holds its secrets and remains hidden to us. Some say the volcano is alive and that the summoners intended it to be this way. Some say it hides and protects the hidden evils from thieves and would be cleansing.
What is rumored is that the mountain is riddled with tunnels created either by those trapped escaping or by those from the outside digging in to discover what laid below.
The power to summon a volcano is currently unknown in the world. No recorded histories are known to mention such a powerful capability and no record of the events surrounding Fort Grimstone are captured beyond the myths of the local Bane followers.
Whatever powers lie within and whatever forces created this mass grave lay beyond the knowledge and even the local history.