TheCosmicKid
Hero
I like [MENTION=71699]vonklaude[/MENTION]'s variation, but it bugs me why the angel would say anything if they don't know it to be true. And if the devil agrees with them, they can run the logic as well as, if not better, than, the PCs and go, "hmm, something's wrong here".
Maybe have the two trapped in magic mirrors such that they can't see or hear what the other one says? Then clever PCs might be able to get more information by relaying the information between them.
Also, I think a devil is better than a demon here. Always lying is consistent behavior, and that says lawful to me. In any case, both types of fiend are normally intelligent creatures who are capable of deciding when to lie and when not as best suits their interests, so to get a nice simple logic-puzzle rule like "always lies" you're probably.gonna have to put some sort of curse or geas on the fiend to force them to do it. Perhaps the same mechanism also stripped the angel's memory. Some effect of the mirrors, perhaps?
And if you're doing that, there's no particular reason you can't make the ANGEL the liar...
Maybe have the two trapped in magic mirrors such that they can't see or hear what the other one says? Then clever PCs might be able to get more information by relaying the information between them.
Also, I think a devil is better than a demon here. Always lying is consistent behavior, and that says lawful to me. In any case, both types of fiend are normally intelligent creatures who are capable of deciding when to lie and when not as best suits their interests, so to get a nice simple logic-puzzle rule like "always lies" you're probably.gonna have to put some sort of curse or geas on the fiend to force them to do it. Perhaps the same mechanism also stripped the angel's memory. Some effect of the mirrors, perhaps?
And if you're doing that, there's no particular reason you can't make the ANGEL the liar...