Can the Battle Harbinger's Empowered Onslaught reaction boost the potency of the permanent* duration Bane/Bless the level 16 Cleric feats provide?
*Until counteracted or dismissed and even then they come back.
No because you can never trigger it using your Eternal Blessing/Bane.
Your deeds have brought your deity’s grace to you for all of eternity. You’re continuously surrounded by a bless spell, with a spell rank equal to half your level (rounded up). The radius is 15 feet, and you can’t increase it. You can Dismiss the spell; if you do, it returns automatically after 1 minute.
Your life has made you a nexus for your deity’s vile power. You’re continuously surrounded by a bane spell, with a spell rank equal to half your level (rounded up). The radius is 15 feet, and you can’t increase it. You can Dismiss the spell; if you do, it returns automatically after 1 minute.
You critically hit and Sustain a battle aura.
Maybe someone could say that you can Sustain it without increase it but honestly this is just a try to exploit it. I don't think that it's valid.
But Empowered Onslaught also states
Choose one active battle aura you have; that battle aura's status bonus or penalty increases by 1, to a maximum of 4. This value remains for the rest of the aura's duration.
Which indicates the triggering battle aura doesn't have to be the one empowered, and Bane and Bless are unquestionably always battle auras. Even if the Eternal ____ feats can't trigger it (and I have my doubts with how Bane has the effect of reforcing the save on any foe who is unaffected on its sustain and thus the reading that the Eternal version can't be sustained period seems too bad to be true)
As is though, spells from these feats (Eternal Blessing/Bane) aren't your 'battle auras' and as such the feat Empowered Onslaught doesn't work for them at all.
"Any feats and effects that refer to a battle aura refers to these spells, regardless of whether they were cast with your standard spell slots or your divine font spell slots."
Spells from Eternal Blessing/Bane aren't cast from any slots at all and so aren't battle auras.
So battle auras cast from scrolls/staves/wands also wouldn't count according to that logic.
Firstly, no, Bane and Bless aren't always battle auras, see above.
........You can prepare only bane or bless in these slots. Any feats and effects that refer to a battle aura refers to these spells, regardless of whether they were cast with your standard spell slots or your divine font spell slots.
im afraid you are mistaken, they are always Battle auras for Battle Harbingers dont matter how they are cast.
but i agree that its a gray area when you cast a spell without spellslots or font
"regardless of whether they were cast with your standard spell slots or your divine font spell slots." dont have to be a exclusive list, its just an example and their intent for scrolls and staff could be there but as i said its a gray area.
Edit: but i do agree that having permanent +4 aura sounds tgtbt even at that level.
Firstly, no, Bane and Bless aren't always battle auras, see above.im afraid you are mistaken, they are always Battle auras for Battle Harbingers dont matter how they are cast.
but i agree that its a gray area when you cast a spell without spellslots or font
"regardless of whether they were cast with your standard spell slots or your divine font spell slots." dont have to be a exclusive list, its just an example and their intent for scrolls and staff could be there but as i said its a gray area.I think doing this you take things out of the context. Full (almost) entry:
"Instead of preparing heal or harm spells with your divine font, you instead gain the battle font, which allows you to prepare battle aura spells. You gain 4 additional spell slots each day at your highest rank of cleric spell slots. You can prepare only bane or bless in these slots. Any feats and effects that refer to a battle aura refers to these spells, regardless of whether they were cast with your standard spell slots or your divine font spell slots."
This whole paragraph is about your divine font only. Then normal slot spells added. And that's all. Nothing else. "These spells" are bane and bless from font slots about which there was the discourse above plus normal slots which added explicitly.
If they really were going to allow all sources they should've written exactly that: "refers to bane and bless spells, regardless of whether they were cast with your standard spell slots, your divine font spell slots, magic items or any other source" for example.
I feel that the comma and word usage suggest more, since they could have used alot clearer words to express that only Battlefront and regular spellslots counted.
but you are right that its speculating on paisos intent, and pure RAW you are correct.
Example of shorter and more clear: "Any feats and effects that refer to a battle aura refers to these spells only when cast with your standard spell slots or your divine font spell slots."
and since paiso spends quite alot of effort minimizing word count(sometimes they have made thing unclear that way) in their books i feel that they intended something more.