To Tame an Archdevil
Vigil Keep is an enormous fortress, hidden within a pocket dimension, designed by the Crusader-Knights of Lastwall to house Mephistopheles, Lord of Caina, the 8th Level of Hell. In addition to being practically impregnable, the only entrance to the fortress-prison is cleverly hidden in the tomb of Odrin, an old wizard from Mendev, who was buried beneath the present-day site of Sandpoint Academy.
The PCs know little about the history of Vigil Keep, except that it was built as a prison for the supposedly invincible Mephistopheles by the Crusader-Knights of Lastwall over a century ago following the Archdevil’s escape onto the Prime Material Plane. A team of archmages, led by Odrin of Mendev was assembled to construct a prison for the Archdevil and seal him within. The mission was a success, although Odrin lost his life in the process. The surviving wizards decided that the entrance to the keep should be hidden in Odrin’s tomb and buried him beneath an obscure village (Sandpoint) in an obscure province (Varisia).
When the Legion of the Iron Crown appeared to threaten Sandpoint with invasion, Nardyn tasked the PCs with stopping the legion lest they free Mephistopheles. Efforts to this effect proved unsuccessful and after the First Battle of Sandpoint, the Lord of the Iron Crown was seen entering Vigil Keep with the Ritual of Archdevil Binding in hand.