Ok... am I blind? I found the cultists under the sewers... they told me to get the rift device. Where the hell do I go now? I've explored every square inch of area under the sewers and cannot find a way to go further down to begin looking for the device. Where's the entrance?

SLIGHT SPOILER

down







When you enter the cult part you can go south (towards the cult) or straight to an apparent dead end. Theres a secret door on the north side of the passage which should turn purple.