Got to know the thieves guild, and their escort, Sara. She showed them how to ID the local traps put down by the guild, brushed Senko up on new (or locally used) sigils of Thieves cant, and gives them a glance at a lower level that might be interesting down the track (Dungeon in Session 21 fyi)
See the crack in the wall for the giant slugs, with one peering out looking, Sara remarks that they function as great cleaners / body disposal systems, but, unlike a giant ooze if you can get into their lair without them being around, there is usually a nice tidy little sum for the taking from all the non-logical matter left over from their victims.
The result of this was, of course, obvious.
Machinations ensued.
An elaborate lure was created to get the Slug from its home (Parallax offering it his head for food), while Justus got in there and looted the (predigested) treasures.
They hit the Central chamber, and a rat appeared, stared at them, and then backed away slowly the way it came.
Rat Cult
The party took a small detour, and, after following a large rat around a corner, was abushed by a swarm falling on them from outlets and pipes and such.
Sir Senko did so breavely flee, as Justus took a large amount of damage, and Parallax lightning breathed (Brothed?) them to a crispy fate.
They then found a locked steel door, and started a war of words with the creatures behind the door, before giving up when the (safe behind a door) rats wouldnt give into repeated attempts to intimidate them.
Who Are The Rats?
A cult of Chaos, they use parts of the crystal below, feeding on it to gain their physic powers.
Now they run through the sewers of the city, building their evil horde.
They can be conversed with, if the players so choose, and may be bargained with to help with the cult below that is seeking to do something to it.
That crystal powers the whole network of the Abjurers, fwiw.
The Trolls
We met some Trolls, who live in the sewer and are friends of the thieves.
They take 10gp tax for new comers, and really, really like apples.
Their Staircase leads to the market.
-30 gp for Troll Transit Levy (Pay Da Fee, Smol Humie!!)