The room was too small to maneuver effectively, leaving our very squishy pseudo-tank to stand in place and take the brunt of the demon's full attack every round. On the other hand, the tank had the demon more-or-less bottlenecked, so the gunslinger could stand outside the room and shoot in, and the cleric could lurk in the small amount of open space in the room and sling spells and heals as necessary. That left Obsidian, standing in the doorway behind the tank, doing her best to buff, pocket-heal the tank, and direct the flow of combat as best she could. Fortunately, the demon's soul-sucking power didn't work on the tank right off of the bat due to a plot point that had occurred earlier, giving the tank script immunity. That didn't mean it couldn't still chew us up and spit us out, of course.
For the first several rounds, it was quite worrisome, as the demon was doing way more damage to the tank than we were doing to it, and its various powers and resistances were reactivating on a round-by-round basis as the wards fell. Obsidian cast a grease spell under the demon, but it made its saving throw and kept standing ("Blast it!"), so Obsidian stuck with pouring hit points back into the tank, returning them at just slightly less than the rate the demon was chewing them up.
At this point, the cleric used her healing burst to mostly-restore the tank, and Obsidian used another of her big heals to top him off-- suddenly we were all at full health again and swimming in buffs, which made the demon begin to think that maybe the combat was not going to go the way it had hoped. It cast a crushing despair on us, which negated Obsidian's buffs (but not the cleric's, leaving us still in a net positive), but with a free round where she didn't have to pocket-heal the tank, Obsidian pulled out her whip and, with no small amount of sass, attempted to trip the demon.
Remember that grease spell? jamesbarrett had ruled that the grease spell lowered the demon's combat maneuver defense by three points-- which was exactly what Obsidian hit. Suddenly, the demon was on its butt and wondering what the heck was going on. It tried to get up and blew the reflex save (Obsidian's charisma is currently 22), and panic set in. The cleric moved in and flanked the demon, enabling the tank to apply his sneak attack damage, and Bam! One less demon in the mortal world, beat by having been tripped by a bard.
Well done, team! Medals all around.
Unfortunately, the wizard who hired us to come down and investigate this demon got portalled-off to who-knows-where before we could stop him... so we didn't get the second half of our payment. ¬.¬ On the other hand, we found some Kewl Lootz in the complex which made up for it. And of course we whipped some demon butt, which is its own reward. As I tweeted last night, "Obsidian doesn't just defeat her foes, she breaks them. With style."
Getting back to town involved a bit of unexpected skullduggery, as the city gates were locked due to catastrophic plot activity. We had to sneak in through the sewers, which of course made Obsidian quite snippy: a running gag through the whole campaign has been Obsidian's outfits getting ruined through the course of adventuring, whether mauled by bears, burned to a crisp, or being spewed with zombie guts, and after managing to defeat a powerful demon without having her outfit harmed in any way, she wasn't about to go swimming in a sewer wearing it.
The net result was she went swimming in the sewer in her skimpy drow underwear, which was not exactly fun either, but kept her outfit from getting ruined. Appropriately enough, their trip through the sewers brought them up into town in the basement of the local bordello, where Obsidian's lack-of-outfit made her fit right in. She did put her clothes on before leaving, tho; fortunately, nobody offered her a job.
All in all, it was a fun session. :) Obsidian's ego, already quite dangerous, is probably going to inflate to all-new highs after having humiliated an ancient demon. It's a drow thing. I also enjoyed the brief bit of sneakery, and actually would have liked a little more of that. Obsidian has an outrageous Bluff skill which she almost never gets to use. They found some evidence of smuggling going on down in the sewers which Obsidian intends to keep in her back pocket in case she needs it for something later.
Someday, this gal is going to sneak herself into a general's camp wrapped up in a rug. I just know it.