Night Hags vs "Just going back to bed"
"Nightmare Haunting (1/Day): While on the Ethereal Plane, the hag magically touches a sleeping humanoid on The Material Plane. A Protection from Evil and Good spell cast on the target prevents this contact, as does a Magic Circle. As long as the contact persists, the target has dreadful visions. If these visions last for at least 1 hour, the target gains no benefit from its rest, and its hit point maximum is reduced by 5 (1d10)...."
Contrast and compare with the wording for long rests: "A character can’t benefit from more than one long rest in a 24-hour period, and a character must have at least 1 hit point at the start of the rest to gain its benefits."
So let's say that the Sewn Sisters rock up in the middle of the night, put the finger on the Cleric, and nobody interrupts the nightmares. Morning comes, people awake, and it is realised that something went wrong and the Cleric didn't get back any spell slots. To my strict interpretation, there is absolutely nothing stopping the Cleric, at this point, from simply going back to bed to try again - and if no other night hags pop by to mess with that one too, it will work. But other people rule it the other way (that the whole day is a wash), and I actually kinda want them to be right. Read strictly, the power would actually be stronger if it was made weaker, because if the victim got any benefit - no matter how small - they would be categorically forbidden from trying to long rest again!
I'm fine with modifying powers. I do it by accident and on purpose. But how did everyone else do it and how did it turn out? Did you harass your party with the Sisters in the Tomb at all?
Posted May 16, 2019, 1:30 PM UTC
I can see the confusion. However, you are still completing the long rest, just without the benefits. The Cleric can try to sleep again the following night to gain the benefits of the long rest (assuming no more haunting or interruption). The hit point maximum drain portion of the haunting sticks around until a Greater Restoration spell is cast on the target.
I can see the confusion. However, the Nightmare Haunting ability specifically says that you gain no benefits from a long rest and the rules for a Long Rest specifically say you can only gain benefits from one rest per 24 hours. It doesn't say you can only complete one per 24 hours, it says you can only benefit from one. As OP said, a strict RAW interpretation allows the cleric to lie right back down and get that rest.
It's worse than that. Greater restoration is of no help. Due to the Death Curse, the hit point maximum reduction cannot be restored until after the Death Curse is lifted [TOA 6].