So, Raphael was outside a cave entrance. He wanted me to slaughter some nasty inside. Raphael is a terribly naughty not-person that I've got no interest in helping in the slightest, but it's good to know there's something extra nasty in there.
Actually, there was very little in there - just a lot of books and an empty tomb with a jillion traps around it. There were also some buttons, so clearly there's more to do. The books explained how to use the buttons, which revealed a secret door. Behind that was a temple to Shar. Pulling the right levers for that, and doing some jumping around behind a statue revealed some nasties who quickly got attacked by other nasties.
I saved the nasties from the new nasties, which helped them believe that I was a friendly nasty. I was figuring on blasting them, but then I noticed they had a flesh golem with a big sack full of hit points. Yeah, better not.
So I talk to them and they told me to go get an artifact and gave me a little bell that let me summon the flesh golem! Well, that's great! I think I can make sure that golem doesn't live through whatever battles are to come. That will make it easier to slaughter this ugly crew.
I head down the hallway toward this artifact thing and... great guns. It's a huge, temple complex with multiple floors and elevators! All this was behind two sets of secrets?? Either something else is going to point me this way again later or a lot of people missed this whole thing. Talk about exploration rewards!
I quickly run into a very nasty group, led by a demon named Yurgir. Ha! He's got fewer hit points than the flesh golem. He shouldn't be too... oh, party wipe. Yurgir is HARSH! He throws out bombs that hurt bad and has some deadly melee attacks as well. After he finishes an attack, he immediately vanishes somehow. His minions are no slouches, either, and I think some of those were throwing bombs as well (or maybe just exploding already thrown bombs).
I spent the whole afternoon trying to fight this guy! Detect invisible didn't detect him at all, for whatever reason. The flesh golem was good for absorbing a few attacks, but ignored him when Yurgir turned invisible, so it was mostly good for keeping his minions busy. He resisted most damage types and was completely immune to fire.
I eventually got him by standing at the top of a broken stairway and filling up the room below with sleet and thorns, so there was only one place to stand without taking damage, then I hit that spot with little AoE attacks. Whenever he got hit, he would show up for the rest of the round, allowing everyone else to wail on him. I guess we were too high for him to throw his bombs, too, as he just kept shooting his crossbow at us. His minions were all busy beating up the flesh golem, which they eventually defeated.
All I had to do after that was clean up what was left of the minions. Raphael will be pleased, unfortunately. And there's still quite a bit of this dungeon left to do!