Help Setting A DC's

[Kesnit]

I am running a 3.5 adaptation of World's Largest Dungeon. Party is LVL 9


Halfling Cloistered Cleric/Oracle
Half-Orc Fighter/Barbarian
Hellbred Binder/Warlock (going into Hellfire Warlock)
Kobold Rogue (NPC I built and gave the party when I kicked out the guy who was playing a Rogue)

The party is in area taken over by Drow and Driders. (The Drow - all males - are slaves of the Driders.) The backstory of this area is that the Driders were doing weird magical research and ended up creating two abominations (Madness, Fiendish Half-Dragon Gibbering Mouther, and Anguish, Fiendish Chimera). The party, who are not murder-monkeys, have already met Madness and Anguish and some Drow who want to overthrow the Driders. The Drow told the party a little of the backstory, including that Madness and Anguish were created by a Drider experiment that went wrong and killed a lot of Driders, including the leader. They were also told that there are rumors of a ritual that will destroy one (but not both) of the abominations, and the ritual is likely in the late-Drider leader's workroom. The party knows where the workroom is, but has not managed to get in there yet because they have not solved the puzzle.

The party needs to take Drider poison, put it on a pointed object - like a dagger and rapier - and stick it in the flesh of a living lock. This will paralyze the flesh long enough to unlock the door. The party knows SOMETHING needs to be stuck in the flesh, but don't know that it needs to be Drider poison.

The party found a clue previously that said "The poison of the Masters can be used..."

The Drow told the party that the Driders are the Masters in this area.

When the last game session ended, the party had just defeated a group of Drow (not the group they are aligned with) and 2 Driders. They will loot, but unless someone remembers the clue and thinks to get the poison, they won't be able to progress through the living lock and find the ritual. The players didn't remember, but that doesn't mean the PCs didn't think of it.

I'm going to give all of them a WIS and INT check to remember the clue and make the connection. However, I don't know what the DC should be. The Cleric has the highest stats in both, but only has a +3 to WIS and a +2 to INT.

[SilverLeaf167]

Well, there are always two ways to set a DC.

Character-based: Pretty straight-forward, but may take some math. What do you want the players' odds to be? Base the DC on their modifiers. If the DC was 13, for example, the Cleric (if he got to roll both checks) would have an approximately 75% chance of succeeding on one or both. If the DC was such that the characters had an average chance of 50% to get it right, it's almost certain that one of them would succeed. You'd just have to figure out the odds and choose what you want.

Situation-based: What would make sense given the actual difficulty of the puzzle? Frankly, if the characters have heard those clues relatively recently and had any reason to pay even the slightest attention, it probably wouldn't be unreasonable to say the answer might be halfway obvious to them, so the DC could be pretty low. Based on the general DC guidelines, somewhere around 10-15.

However, with a total of eight attempts being made, the DC would have to be pretty high for there to be any real chance of failure. Question is, what will happen if they don't figure it out? Are they just screwed, or can they deal with the abomination in some other way, without the ritual? If it's absolutely vital that they get inside, you might want to throw some other clues at them to refresh their memory and ensure they get in, but if the ritual is just a bonus, a higher DC wouldn't be as much of a problem.