Regarding moon magic, in the Dragonlance series Krynn has 3 moons: Solinari, which gives the Good-aligned mages their power; Nuitari, which gives the Evil-aligned mages their power; and Lunitari, which gives the Neutral-aligned mages their power. Solinari is white, Nuitari is black, and Lunitari is red.
I think. It's been a long time since I last read those books, but it's basic Dragonlance 101, from
Dragons of Autumn Twilight.
And no, you can't get away with saying "it's fantasy so physics doesn't have to make sense." Even magic systems have to be consistent in-universe. That's why some people take issue with how many wish spells Raistlin casts in
Dragons of Spring Dawning. He shouldn't be able to do that, yet he does. I get that the authors took artistic license, but since that trilogy is based on a series of 12 dragon-themed AD&D modules, they should have made more effort to write within the rules.
Speaking of in-universe consistency... I still have to figure out how to explain the fantasy/magic elements the Kingmaker developers threw in at the last minute. The RL explanation is probably that they ran up against a deadline and had to wrap things up quick. Plenty of reviewers say the game should have had at least one more chapter, more likely two, and the introduction of magic at the last minute was a cop-out. And they switched animation styles near the end as well; it's obvious from the way they drew Randall and did the animation when he finds the Crown of King Edwin the Great, and when he in turn is crowned.
That said, the introduction of magic has allowed me to take Randall's character in a completely different direction than I'd originally planned. I'm incorporating a lot of music into this, particularly music from various Celtic artists, heavy on flute and harp music (ie. I'm envisioning Enya's "Only Time" being played at Duke Edvar's funeral as the background for a montage of memories experienced by the people gathered there to mourn him). And there's a reel from one of my other games that has nothing to do with this, but I really, really want to incorporate it and write words to accompany it. The problem is that I can't remember which of my games it's from. I do know it's probably one I bought last fall so that narrows it down some, and is one of the time management/archaeology adventure ones. And there's some music from one of my World's Greatest Cities Mosaics games that would fit in perfectly - mostly piano, but if Duke Edvar can wear suspenders eight centuries too early, I can have somebody invent the harpsichord a few hundred years too early.
As for what magic has to do with the music... I'm partly drawing on my own experiences. Some people experience music as colors, and that's true for me to some extent. At some point in his life (in his teens, I think), Randall is going to start experiencing odd visions and extra-sensory things associated with music. He experiences it as the world singing to him, in a vast harmony of voices and instruments. It's overwhelming at first, but as he gets older he learns how not to let it overwhelm him and discovers that it gives him the ability to compose music that affects listeners' emotions in a much deeper way than usual.
Now if I can figure out if the physics of music can be connected to the Crown's ability to turn a villain into a statue of wood, that's that part of the game figured out and the deus-ex-machina ending explained.