Lost in the Sewers: Part 2

Stumbling through corridors the come across a door with noise behind it. Light comes from behind the door.
 
Busting into the room five robed figures are standing around an altar in the left hand wall of the room.
On dispatching the robed figures (the assassins who were after the Burgomeister) the party investigate the altar.
 
Moonstone pentagram made of wavy lines with a lozenge shape with an eye in the middle.
Above the altar are some sheaf's of paper. At the foot of the altar is a font and a small chest.
 
Opening the chest the party find coins and gems. The sheaf's of paper seem to be loose sheets tied together with various runic languages on them. On examination the party can gather some Infernal and Brythonic words making reference to the "star-god".
 
Below the carving on the top of the altar, is a recess holding a small amulet on a plain chain. Fleec decides to keep the amulet and offers his share of the gems for the amulet. Grimmaz agrees.
 
Stumbling onward through the corridors leads to a disused cobweb filled part of the sewers.
A spider-web filled room (complete with spider)
 
Methane pockets explode when meeting the torches.