Let Me Hear Some Soul

Question: Do you think that Heku practitioners could extend their influence over soul anatomy to messing with other pantheons' ideas of the soul? Say, for example, manipulating a Teotl Scion's nahualli?

You're getting here into some very dangerous waters, where the deep, deep seas of Comparative Mythology and Game Mechanics meet and become choppy.

The answer to this is no, for a few different reasons. The major problem with this, from a game-balance perspective, is that that would automatically make Heku very, very overpowered. Many different pantheons and cultures have different ideas of what the soul is and ways that that could be expressed in Scion, from things that happen in their PSPs to custom Birthrights to interactions with their pantheons or lesser immortals, and since they're not all the same, it would require a pretty hoss set of powers with carefully-delineated effects to find good ways to interact with all of them. Heku is way not equipped to do all of that, and furthermore it would severely penalize people in other pantheons just for getting in touch with those things - if they have to voluntarily put a lot of time/effort/Birthright points into even getting that thing, and then the Heku guy can just fuck with it, why would they both doing that instead of getting some other relic that nobody would get to unfairly screw around with? What about cultures where the soul and its disposition is being handled primarily by APPs - is the guy with Heku just royally cheating people with the Death purview, too? Where are you drawing the line on what a "soul" is and what powers can and can't affect it?

So game balance is obviously an issue here. But, more importantly (at least in my opinion!), Heku is specifically designed to work with the Egyptian idea of the soul. Egyptian deities and religion believe in that idea of the soul, and interact with the soul that way; as we say every time we talk about comparative religion, it's their mythological truth. But it's not the mythological truth of other pantheons that have entirely different conceptions of soul, which vary widely and are often totally incompatible, and it doesn't make sense for the Egyptian "truth" to intrude on, for example, the Aztec "truth" and invalidate it. From the Aztec perspective, the twin-soul nahualli is the truth of how souls are put together, and it's the Netjer who have some weird exotic theory, so why do the Netjer get to impose their truth on other pantheons, when the same is not true in reverse? It's true that the Netjer have powers over the manifold soul of Egyptian mythology, but that doesn't necessarily translate to having power over everyone's soul ever across the universe, just as an Orisha Scion's control over her own destiny doesn't necessarily mean that she gets to invalidate every other culture's notions of Fate that don't match up to hers.

This is a place where, because All Myths Are True in Scion, you need to decide how it can be true that the Egyptians believe that everyone has an eight-part multi-soul but the Aztecs believe that everyone has a dual-animal soul but the Inuit believe that everyone has a triple soul of which one is the quality of breath that keeps them alive, and so on and so forth. All of them are true, but they cannot intrude on and make one another untrue without breaking the game. One answer might be that because the Egyptians have the power of Heku, they can interact with their own souls (and to a limited extent the souls of others) in the context of the eight-part Egyptian soul, but that that's a characteristic of their PSP, not a universal truth of how souls work. Another might be to say that everyone within the Egyptian religion's range has the multi-soul - after all, they all want to be mummified so their various soul parts head off to the afterlife correctly, right? - but that this only applies to Egyptian people and not to anyone else. Yet another option might be to say that all people everywhere have all the different cultural conceptions of souls, at once, and it doesn't matter because it only comes into question when someone has a set of powers that specifically affect one of those setups. Or maybe you have yet another idea for reconciling all these things that works better for you. I don't know, because I don't run your game.

But I do know that every culture's religious ideas of souls must be equally valid for Scion's universe to function without one pantheon being "better" or "more important" than the others, so while you can have powers like Heku interact with other people in some senses, you can never have them override another culture's conception of how things work. Heku and nahualli are both concepts that work with the soul, but they're not the same and it would be very difficult to find a way to make sure that not only those two interact in a balanced way, but that every kind of soul expression in the entire game does, too.

At any rate, Heku does not affect either other peoples' Birthrights or their PSPs, so no matter what way you run nahualli, the powers of Heku shouldn't be applying to them. Both are cultural expressions of a pantheon's religious idea of the soul, but that doesn't necessarily mean they're the same or compatible, or that trying to make them so would be good for the game.