I'd like to see if we can't compile a list of all the ways mundane humans/animals/whatever can gain a Might Score (any Realm) that have been explicitly detailed in the rules.
Noble's Parma, I can think of a decent few off the top of my head, mostly for acquiring Magic Might. Obviously, anybody with strong desires might get Might when they die by becoming a ghost, but I dunno if I'd call that explicitly detailed. What is explicitly detailed is that a character who dies with a True Faith score becomes a Divine being with Might. Amazons also get (Magic) Might when they die and become ancestor spirits. It will probably only happen to magi and maybe some hedgies in practice, but in theory any mundane human, animal, or item can acquire Might by staying in the Magic Realm (or something akin to it, such as a magus comprehending a Twilight) and acquiring the Transformed (Being) Virtue. Gruagachan acquire Might naturally when their Warping Score gets too high (10?) since they become trolls. Magi in the appropriate Mystery House/Cult have a number of resources. Greater Elixir, Living Ghost, Ascendency to the Hall of Heroes, and dying with an Inner Heartbeast are all avenues for those seeking Magic Might, while those with a Faerie inclination will find their home in Becoming.
I think you need to already have Might to use that Ablating option, actually.
Though while we're on the subject of diabolism, a magus with access to the Forsaken duration could, in theory, invent a version of Exchange of the Two Minds with said duration. If you take the RoP books to heart, this will only really work with Magic creatures; none of the other Realms' beings have minds to exchange with yours.
It doesn't say that. It only states what kind of characters can not do that (for example, if you have the Gift, you cannot have Infernal Might). If a sorcerer wants to Ablate himself into an infernal human, he can do that.
Technically fable points can give you an englamoured body and a Might Pool, but not a Might Score and in particular no Magic Resistance or immunity to warping (RoP:F, p.26). Also, the result only affects you while you remain in faerie; once you are back to the mundane world, you go back to your mundane self (although the effect reasserts itself if you go back to faerie).
In other words, the Core book is reasserting its prior statements in order to remain relevant "No, scratch the actual Might out! Did you read this little sentence here? Unless you intend to become a permanent member of the Realm, Faerie has no way of granting MR! In any scenario! Ever! None!"
I had forgotten I wanted to go back to check this; I finally remembered. It looks like your use of the terms does not match RoP:tI's use of them. If we look at the specific case of increase Infernal Might Score (via Virtues), it talks about "points" (lower case) of "Infernal Might," not "Infernal Might Score." If we look at a specific case of gaining points in the Infernal Might Pool (via CrVi), it talks about "points" (lower case) and "Infernal Might Pool." The wording for Ablating very nearly matches the Virtue and doesn't really resemble the CrVi spell.
Also, what would be the point of pointing out who can and cannot have Infernal Might if all it does is replenish Infernal Might Pool? Then it would apply only to those who already have Infernal Might, making that sentence pointless.
I don't think there is a need. It appears to be the only reading of that part of Ablating that makes internal sense and the only reading that is consistent with the other parts of the book. The word "Score" would have been nice to include but is consistently not included and so is not necessary here.
It makes sense that it would only work on people with Might because there is a virtue in rop:ti for being a character with might, Demonic Blood.
if you weren't lucky enough to be born to a demon you can get around this by becoming an infernal ghost.
I'm sorry, I don't follow this logic at all?
There exists a way to get infernal might as a character, so one (and only that one) of the four Goetic Arts require a Might score?
Without actually stating so explicitly, anywhere?
And here I thought the Infernal was all about the lure of easy power?
I think the Divine is the one with the lure of easy power. I mean, if you spend 10 seasons bumming around while seeing the [strike]tourist attractions[/strike] holy sites you can get a big fat major virtue. The infernal is the one with the lure of encouraging you to be a selfish asshat. Plus the Divine has a much better retirement and vacation package. And management is much nicer.
I think "having to not sin (often)" is a much bigger limiting factor than you give credit for. Especially since, from a modern perspective, a lot of the things considered sinful in the religion of the times would seem totally arbitrary. They weren't, but most certainly could be seen as such. And that's just to keep regular ole Divine power. I should correct one thing: spending ten seasons bumming around religious attractions does not give you True Faith. It just gives you a Faith Point, which, in absence of the True Faith Score, is pretty much a stack-able Confidence point.
As somebody who plays Divine characters almost exclusively, I'll tell you I've only ever played one character with True Faith to any degree of success. This despite the fact that True Faith is one of the most useful Divine Virtues in the game, giving you Magic Resistance, effectively self-replenishing Confidence, and free access to a Divine tradition. Why? Because if it's being treated with the appropriate amount of respect, True Faith is a really hard thing to gain and hold on to. Roleplaying the intense, all-encompassing, other-personality-trait-destroying piety is part and parcel of the concept, but the limits to character actions and amount of stressful attention is beyond compare.
An only slightly exaggerated account of how True Faith should work by paradigm/canon:
"Alright, I'm just gonna take a walk down to the market to buy some fruit." "Why do you have money? Couldn't that money go somewhere better, like donation to charity? In fact, shouldn't you be assisting the sick right now? While you were thinking about it, two of the Princes of Hell snuck up on you. Roll Initiative... Or let them take the first free shots, because there's a tree falling on a helpless kid over there. And another kid is pickpocketing that money you were going to buy fruit with." "Oh, so it's Tuesday?"
Now, very few SGs are actually going to throw something that ridiculously contrived, complex, and un-fun at you, because this is a game. But in a lot of ways, that's how it feels (or should feel) every moment playing a True Faith character. You like playing the character constantly guiding others towards moral righteousness? Not enough. The one constantly being helpful and charitable to everyone they meet? Not enough. The one carefully avoiding every act that could possibly be construed as sinful or evil? Not enough. The one who maintains aforementioned careful avoidance of evil while using everything else at their disposal to fight evil? Not enough. Mix it all together? You're almost there. And fail at any of those things by much for a second, you have a crisis of faith, go spend a story atoning.
Infernal power? Even the really high-end stuff? If you've got a decent head on your shoulders to avoid screwing yourself on badly-worded deals with demons and such, you can be a badass among badasses at the low, low cost of your immortal soul suffering forever. Or if you don't want to have to be that careful, you can still usually get gifts from demons or diabolists and never have to deal with their dangerous sort of crowd again... As long as you don't go doing anything reckless like confessing.
(Though honestly, Faerie is where it's really at. If nothing else, you can probably arrange to be surrounded by whatever you want to be surrounded by, because, y'know, Faeries. )
Anyway... I might argue against Ablating working that way in my games. It seems like it could be open to self-looping, and then I'd have to question why there isn't just one demon in Hell with arbitrarily high Might.