Soul Debt on other skins

When someone chooses the Infernal's "Soul Debt" move off of the "Another Skin's Move" advancement, how would you play it? It gives you candy in exchange for the Power getting strings, and when you hit 5 strings it triggers your Darkest Self. For Infernals, this means that the power makes big demands of you that you're compelled to give in to, and when you fulfill one it loses a string.

But if another skin takes it, they've got a different Darkest Self, which doesn't get rid of the strings. The options seem to be a) go to the Infernal Darkest Self, b) Go to the character's Darkest Self, and wipe strings (or at least lose 5 strings, since you might have called on your bargains while in Darkest Self) when they hit their native escape clause.

Obviously this could depend on the fiction. If a werewolf takes it to represent him drawing on his animal self/moon powers, making him more likely to snap, then option b makes more sense. But does anyone have any input at the relative merits or problems of either approach, or some other ways to handle it?

So, examples are always useful:

Tucker the Werewolf takes Soul Debt. The dark power wracks up 5 Strings on him. Tucker's Darkest Self is triggered.

As written, without doing any 'house ruling,' Tucker will escape his Darkest Self with the usual escape clause, and then Soul Debt will immediately trigger him back into another round of Darkest Self. Right?

Except... the dark power can spend their NPC Strings to offer Tucker experience to do what they want, to come out of nowhere with a hard move, etc, etc. If I were MCing this situation, I'd definitely be spending my NPC Strings in this situation. The dark power has been giving candy to Tucker, now Tucker's at his most useful and dangerous, so it's time to pull those Strings and get what it wants out of him.

Alternately, when you stat up the dark power (as a Threat, which you should definitely do!) you can give them the custom move: "When a minion is at their Darkest Self, [this dark power] can offer them tasks. Each task completed removes one of [this dark power]'s Strings on them. If there are no more Strings, the minion escapes their Darkest Self."

That custom move leaves non-Infernal characters with the same Darkest Self deal as Infernals have, which is one good way to handle it.

Cool, that makes sense. The Custom Move seems like the less nice (and probably more fair) option, since it doesn't offer XP for your bad behavior.

It's also worth mentioning that Tucker could use <i>shut someone down</i> to strip his dark power of some Strings.

Okay, that's interesting. I was wondering how to portray the Dark Power in gamespace, other than sort of global custom moves. Like, "do the weird occult drug, it gets a string on you," which it will probably use by whispering in your ear and offering you XP, or whatever. But I guess nothing stops the players from back-chatting, given a two-way avenue of communications. Or even back-handing, given a physical manifestation?

I played in a Monsterhearts game over the weekend. I played an Infernal.

There was a scene where the Hollow ran away into something worse. The something worse was my Dark Power. The Dark Power offered him a soul (of sorts) if he performed some task. I forget what now. Killing someone maybe?

Mechanically, when he did it he got the Soul Debt move, but with only one Bargain.

So having the Dark Power manifest like that is definitely cool.

Also, back-handing the physical manifestation of your Dark Power would be awesome with the move that allows you to remove strings when you lash out.