So in the pitch video, Josh mentions that magic in the setting is going to revolve around characters' souls (this will also play heavily into the game's plot, allegedly). Not only is this a potentially interesting point of origin for magic, but it establishes something like a system of metaphysics for the game's setting, something that can be explored in interesting ways.
Some examples: So people in this setting have souls. Therefore we can ask:
- What is the substance of a soul? Is it connected to the mind, or the body, or both? How can you even read a person's soul?
- Does one soul differentiate from others based upon someone's characteristics? Do different races have demonstrably different souls? Do different genders?
- Do one's actions affect his/her soul? Does experience in the world foster soul growth? If I commit senseless violence, does my soul reflect that as well?
- Can a person's soul be damaged, removed, controlled or captured? If so, what happens to that person? Can that malady be mended?
- Do all creatures and living things have them (failing that, a "spirit")?
- It's already been said that the PC and his companions will have "high-quality souls" (paraphrasing here). How does one make that determination? Is a high quality soul born or made?
- What of people with "broken" or "anemic" souls? Are they naturally incapable of the things that people like the PC can achieve? Do strong-soul'd individuals pass on that trait to their progeny or is it random? Would we see social caste systems emerge from this "natural order" favoring those with better souls?* What if a race does not seem to have a detectable soul? Are they thought of as monsters, as animals to be exploited at the whim of the soul'd?
- Can one's soul be sick, or abnormal? What terrifying or intriguing ways can that manifest?
Just riffin' here, but I think there's a lot to explore here!
* - I don't much like the show and I think it completely squandered its potential w/r/t exploring this sort of thing, but Last Airbender: Legend of Korra touched on this sort of dynamic with the whole "bender / nonbender" political subplot.