So.... I can use it once per combat no matter how many combats there are during the course of Haunted Boughs? I'm just trying to clarify since before you were stating "one time" and "one attack" which seemed clear, but then you threw in this "one entire turn" phrase.
Hm, I'll try to clarify it better...
It's pretty common in Warhammer Quest for an item, character skill, or other optional effect to work "once per adventure." Also prevalent, although a bit less common, is for some boost or bonus to last "for one adventure." The default adventure, like if this weren't a campaign but was just a dungeon generated using the game's dungeon deck, is something like 10 rooms. But the Roleplay Book also allows for one dungeon with multiple "deeps" that are themselves about the size of a typical dungeon, and even provides a detailed example with "Death Below Karak Azgal" (which I used in our campaign). The book is a kinda open-ended about how "once per adventure" or "for one adventure" function in the case of dungeons that chain multiple "deeps" together. One interpretation might be that
everything refreshes between each deep. This would be good for your "once per adventure" items and skills, but it would drastically weaken effects that last "for one adventure" or "can be used any time during the next adventure" because they'd go away after just the first, and presumably easiest, deep. You wouldn't have much incentive to make an offering to the gods at a temple if it could only give you +1 Strength for the first deep of your next adventure, leaving you with nothing to show for it later on in the dungeon. A second interpretation would be that all of the items and skills only refresh once the entire dungeon is completed. That would make the "for one adventure" stuff good, but it would weaken the "once per adventure" stuff. You'd probably try to reserve all of your items and skill for the last deep of the dungeon, assuming I told you which deep was the last one (in Karak Azgal, I did not tell you). So I'm going with a "best of both worlds" approach. The stuff that can be used once (or more than once, in the case of Throg's Chalice of Night) all refreshes with each deep. If you're facing a tough monster and want some help, you could activate your stuff to help you out of a pickle, and it'd all recharge again for the next deep. Meanwhile, the stuff that lasts for a dungeon and then expires or that can be used one time within a dungeon doesn't go away between deeps, it sticks around. So the temporary boosts Carrow got from praying at the temple or that Tomas got from wizard school stuff, those won't expire before you even get to the magic tree. They'll last for the whole rest of the "dungeon." I planned this one out to be much bigger than Death Below Karak Azgal, with the deeps so far being...
-Middenheim Intermission
-Cleansing the Temple
-Traversing the Pine Crags
-Haunted Boughs
OK, that's a dirty lie. I didn't plan out Middenheim Intermission. It just sort of happened impromptu. Anyway, because it was so big and because I figured the characters were going to need to level-up at some point, I set the cutoff for stuff that lasts "for one adventure" to end with Traversing the Pine Crags. Consider the previous "adventures" to be Volume I of The Sylvan Epic. Volume II starts here.
Anyway, if an item that can be used once per adventure is a weapon, usually that means its ability is good for one single attack within the course of an adventure (or deep). The Axe of Slaying isn't like those other weapons because it can be used for an entire turn, rather than for just a single attack. i.e. Dorgath's Great Axe has a Death Rune from the Dwarven Guildmasters, so it can have 2D6 added to an attack once per adventure. Dorgath has an Attacks characteristic of 2, so he normally gets to swing his axe twice per turn. Only one of those attacks would get 2D6 damage added to it, then that ability would be "on cooldown" for the rest of the adventure. If he used his Death Rune on his first attack, then the second attack within the same turn wouldn't get the boost, and neither would any other attacks for the rest of the adventure. It'd be on cooldown. Done until the next "deep." The distinction with the Axe of Slaying is that its ability functions for a whole turn,
no matter how many attacks are made with it during that turn. Let's say Kelgar blesses Dorgath with Vanquish, giving him +1 Attack. And let's say Dorgath also uses Flash Powder, giving him +1 Attack. This would mean Dorgath could activate the Axe of Slaying and use it to make four attacks, each of which would hit for a D6 worth of D6 damage. That wouldn't apply to future turns within the same combat. And it wouldn't apply to future combats within the same adventure. It would only apply to attacks made with the axe within that turn.