Sewer Trolls are higher level trolls found in sewers. There are several varieties, though they all look identical. They have a slightly darker complexion than a River Troll, and wear a more yellowish shirt. The varieties are classified by location and special characteristics.
This is not a normal Blue Sewer Troll, since it doesn't drop Blue Bandanas, but instead always drops the Blue Key it guards. However, you can use this key to enter the Blue Gate to face the Blue Sewer Trolls. There is only one Blue Key Sewer Troll. Players must take turn killing him to gain enough keys for a group to enter the gate, if they don't already have them.