Sigmarite Warhammer 'holy' rule

I am about to start a Sisters of Sigmar warband and don't want to get this rule wrong. Firstly the way I read it I would get +1 to wound vs an actual Possessed model, not everything in that warband, correct? Secondly, the Sisters rules were written before Carnival of Chaos, so they don't mention any bonus against Daemons. Is there any FAQ that fixes this?

The most common accepted rule is that it affects ONLY the possessed models, models with undead rule, and models with daemon rule (mutant with demon soul also?). But as far as I know, people have been playing that rule both ways, only certain models or the whole band, to keep it simple.

I've met peple playing the sigmarite hammer and similar weapons and spells affecting possessed, mutant and magister models, beastmen with mutations, models with the rule undead, and the whole carnival of chaos band. House ruling it that way to give the Sisters a boost, and nerf Carnival a bit, regardless the multiple interpretations of the sigmarite hammer makes some sense. Allowing the Sisters to beat to pulp the whole Possessed band with hammers doesn't really have much sense from balance perspective, as Cult of the Possessed are dangerous if live enough and the possessed becomes a killing machine, but they aren't one of the most powerful bands by any means.

The most recent "official" FAQ is 12 years old, so... Getting your group to agree to a house rule is best.

+1 to bitxo

The Sister's Holy Hammer affects the "Possessed" and those possessed, not the whole warband. And as the Undead, just those with that special rule (vampire, dire wolves, zombies) not the others in that warband (necromancer, dregs, and ghouls). The original warbands of the core book each had a bonus and penalty build into them. Like the Witch Hunters special rule was against the Spell casters themselves not the whole warband that had a magic user.

That being said, I would say and the "Demonic" would also fall in the same category and "Possessed" since not all the COC have the Demonic rule, not all the COC would be affected in the same way from the Sigmarite Hammer.

I play the COC quite well, and would see the Sister's hammer as quite a threat, and would agree still, the Demonic rule the same as Possessed special rule for game play. But before I would give the Sister's the advantage in a fight, remember the only Demonic COC are the Plague Bearers and Nurglings, and the Cart if you use it as a playable henchman. My group mostly uses the cart like a Standard, it never goes into battle itself, just stays on the edge table.