Then we get into the question of what is the soul if not the seat of consciousness, and then can I avoid hell by transferring my 'self' (consciousness) into a new body and letting the discarded soul go and suffer for eternity?
Maybe a demon can't attone by himself, but with the Christian thought that God can forgive - so maybe he might forgive an angel...
Well, the hermetic answer is "yes, temporarily" - that's a Rego Memtem effect. (AM5th, pg. 152). Minds and souls are different, and you can swap one but not the other. It's still a limit of Hermetic Theory that you can't do it permanently.
Well, it's central to Christian theology that forgiveness and reconciliation with God is only a step away from anyone who chooses it - but a demon, by definition (or at least according to the definition in RoP:I), won't ever choose that. So it's not so much that God won't offer it - it's that no demon will every truly ask for it.
I've mentioned this on other threads (I think), but my interpretation of this is that angels and demons are non-temporal: ie, they exist outside of causality (which seems to be backed up by their descriptions in RoP:I and RoP:D).
Asking one to atone for what they've done is a non-sequitor: you can't repent (ie, truely understand that something is wrong and that you shouldn't have done it) if you are, in that moment, choosing to do it.
Or to put it another way: if a demon ever truly repented, they would retroactively never have become a demon to begin with. So while they have free will, they will always, by definition, choose evil. Anything else sets up a paradox.
Paradoxes are not necessarily evil.
Cousin Bob
True - I mean, you could run a storyline with that as the conclusion with the timeline collapsing, and then in the denumont show the reality re-write. If set up correctly it would probably be interesting, but I'd argue that having to re-do however many seasons of XP would be a serious hassle.
I mean, it could be run as a sort of mini-apocalypse, in the sense that the world literally would end if a demon truly repented (like in Dogma, sort of) - only in this case, the catch was that it's immediately replaced by an almost identical reality.
Depending on how far back that change goes, this could lead to some very interesting campaigns, especially if for some reason the players are immune to the change... and the bigger the demon the greater the change: for example any number of small changes far enough back in history could eliminate the Order of Hermes entirely... aside from the PCs who managed to bring about the repentance of the demon...
Secrets can be false.
We're dealing with a Schroedinger's Demon, the demonic state of which is undefined. Which is the point: it's undefined. On one hand we have creatures who are incapable of redemption. On the other we have an omnipotent God, who therefore must by definition have the power to redeem a demon. Immovable object, unstoppable force.
I applaud the text for leaving it in this state. Doing otherwise closes story possibilities.
There are obviously no rule covering that. And I think the purpose of not having rules or explicit mention of it is to keep it rare and YMMV basis. Kid Gloves mentionned several cases from rulebooks that implicitly suggest that it is possible to change realm and nature.
So my reading is: it is probably possible, but extremely hard/rare, thus purely depending on the ST needs and will. Otherwise, you can be sure that half of the PCs will have that as part of their background or objective 
... just to be even more a unique snowflake than what is already possible.
My personal theory is that ArM demons cannot seek atonement - while they may be able to feign comprehension of virtue (they don't have or need the ability to reason, but they may be able to intellectually process the idea that humans act in this fashion), they are not capable of asking for divine grace. Whether this is because demons have made an irrevocable choice at their creation (as Thomas Aquinas argued) or because demons still exist to serve the Divine (as Judaism posits) won't be known short of the Last Judgment.
If a demon were to be saved, it would be a miracle. God can and does make exceptions - there's in-text examples of Him granting sainthood to a dog, and of Him accepting a posthumous baptism and freeing a soul from Hell. If it's not a true demon, an infernal being may still be able to repent. And finally, "repentant demon" is an excellent role for a faerie to take on.
Hi,
It is probably exceedingly difficult, maybe impossible, to discern the difference between a faerie doing a very good job at playing a demon and a real demon.
There are probably a lot more of the former running about. It takes just one good story about a demon for faeries to abet more.
As noted in the core rules, the Hermetic perspective of 4 realms is not the only perspective.
The Hermetic perspective might be wrong: They're all faeries. 
/2 A flaw in Hermetic Magic makes this impossible to detect.
So if you want your demon to be redeemed, just make him a faerie that looks like a demon.
But really, I like the notion that only mortals are capable of real change.
Anyway,
Ken
Hi,
Another thought about demons, AM-style:
Demons are known to be masters of deceit, but we spend less time considering the opposite side of that coin, that demons have been mastered by deceit.
That is, a demon might be totally, irredeemably evil yet not know it. It might express completely good intentions and really believe that it believes in its good intentions. It will come off as earnestly trying to be helpful, and really think that it is trying to be helpful. But ultimately, it is a demon. Everything it does will turn bad, for all the best reasons. It might plan very hard to do good, but we all know how bad demons are at planning anything at all.
It could be said that some people come off like this. Certainly this happens all the time in genre (not necessarily fantasy) fiction too. You know, the charming boyfriend from the past who is hard to ditch and he has all the best intentions in the world, yet for all the leaves he has turned, somehow he always ends up on drugs, doing crime, being abusive, and the people around him end up getting the worst of it because it wasn't supposed to go down that way.
So when it comes to redemption, ok, we have a demon that thinks it is redeemed, and everyone around it thinks so too. Great climax for a TV season. What could possibly go wrong?
Anyway,
Ken
Actually Colossians 1:20 says
So, from a real world theology standpoint (rather than RAW) a case can be made that limiting the redemptive sacrifice of Jesus to humans is overly limiting.
Or maybe when a Christian demon is redeemed they become a Jewish demon, tempting and punishing the wicked in the name of God instead of in opposition to him.
Because it is worth keeping in mind that we are not dealing with a grand unified theology here...