Greater Immunity specifically states that it protects from both mundane and magical versions of the thing. Does this wording intentionally exclude Divine, Faerie, and Infernal? This is a supernatural virtue, and not a Hermetic one, so I presume those would all be included.
If my character has Greater Immunity to Fire, and a demon slings hellfire at her, should she be incinerated?
The words "magic" and "magical" sometimes refer specifically to supernatural effects aligned with the Magic Realm, and sometimes to just anything supernatural. This can be confusing, but it is what it is.
In this particular case the immunity is probably intended to be towards all kinds of fire - mundane or supernatural, regardless of realm affiliation.
Or perhaps everything but divine, at the discretion of the divine. Divine stuff just works that way sometimes...
I would rule it as all fire, but having some exceptions related to how the power was granted is always a good thing, Achilles is more interesting because of his heel.
I lean towards all Mundane, Magic, and Faerie fire always.
Divine fire most of the time, though the Divine could always decide it doesn't. Mostly it would need to be something big (major miracle or an Angel doing it?) to get around the Immunity, but if it fits the Divine's plan then a lowly priest with a torch might be able to get through.
Infernal fire all of the time, though actual 'Hellfire' is not the same as 'Fire'. Don't give everything Infernal 'Hellfire'.
The Divine follow the same rules as everyone else. It doesn't just get to decide not to.
The exception is Miracles directly from God Almighty. They work however He wants them to work, overriding everything else, and nobody else gets a say.
But the regular, mortal, miracle-worker is not much different from your regular mage, other than the source of their power.
I always interpreted lower power miracles as direct acts of god, the only difference being that the petitioners could not petition for a greater intervention.
Still agree that the divine should follow a rule, wherein the intent of the miracle is important.
A flame that is miraculously kept alight but it would not pierce the immunity because that is not the miracle in effect.
But a sword imbued specifically with the power to kill people immune to regular steel would pierce the resistance but has no miracle that prevents it from being destroyed, even by hermetic magic.
Both are divine effects, but only one would pierce the resistance.
Divine methods and powers, or creature powers used by divine creatures, and the like are not direct acts of god. God has merely granted the person or creature a bit of his power that they can use as they see fit.
Which is why practioners of divine powers can sin with them, and act against God's will.
If they do it too much they are likely to lose the powers, but until then they can act as they please.
Direct acts by God on the other hand will obviously never work against God's will, and there is nothing else which can stop or block them, or dispel them.
I would say that "if the divine says it doesn't apply" then that is a direct act by God, even if the underlying divine power is not.
Fun fact, Achilles wasn't invulnerable at all, just the best greek warrior. Which is how Homer created him (where is the heroicity in a warrior that thinks he can't lose?). The invulnerability, shot in the heel and all of that stuff was invented by Stacius on the 1st century DC.
Sorry for the off-topic comment, but I absolutely agree that a character is more interesting when he have more weakness and limitations. Which is why Homer's mortal Achilles is way more interesting that Stacius' goodlike-but-in-the-heel.
And by 1220 surely all faes playing Achilles are doing the "oh you have to hit me in the heel" silly thing.
That explains why they never mentioned it in the illiad.
But it also raises the question of what is actually in mythic europe?
The first century is closer to homer than the 13th is to the first, so for medieval person they are both ancient and would likely be regarded as myth, and given the same validity given that they are not inconsistent.
I guess it doesn't matter in this specific case (barring time travel) since Achilles has been dead for over two and a half millennia by the 13th century but what about robin hood?
I guess that's going even further off topic on this thread than you already did, I should probably just open a new topic.