Cleric Bob has hit on an idea to try and compel an orc that attacked him (and is now deceased) to speak the truth so he can find out where their stronghold is.
Cleric Freds plan is to cast Zone Of Truth that has an Area of effect and states:
Creatures within the emanation area (or those who enter it) can't speak any deliberate and intentional lies.
Then use Speak With Dead (Target one dead creature) to get a dead orc to talk; is this plan as cunning as a fox that is professor of cunning at Hogwarts university, or is it doomed, flawed and wrong?
Best Answer
Side-stepping the issue of whether or not zone of truth can affect the dead entirely...
Corpses under the effect of speak with dead cannot tell a deliberate or intentional lie to begin with – in fact, they have no intent. That still doesn’t make them reliable sources of information.
The corpses just babble mostly-incoherently:
As the second clause indicates, the corpses of foes may have been more difficult, but even those that would have wanted to help you in life are incapable of doing so clearly. There is no thought going on; the corpse is basically just replaying some memories from life in response to questioning, and that’s all it can do.
So whatever comes out of the corpse’s mouth is inherently unreliable. It may be misleading or even inaccurate, if it’s even intelligible, even if the deceased would actively want to help you. This is not a deliberate lie, just a failing of the state that the corpse finds itself in.