The Tower of Startha is a massive, subterranean complex built by a mad mage that extends deep into the earth. The "tower" purportedly extends 10 stories beneath the surface, with each level populated with terrible traps and beasts. However, the dungeon is rumored to contain many powerful relics, including an artifact in the 10th level that is apparently capable of fixing anything.
The doors to the dungeon had been locked for many years by a powerful and impenetrable incantation, but in 989 IaC, the doors were broken open by the Green Hand with the Unknown, an item capable of opening any door. Since its opening, people of all kinds have flocked to the dungeon in an attempt to claim its riches.
The witch the Ossuate sought to open the tower in order to claim the mending artifact, as she wished to used it to revive the Great Colossus.