This isn't something I really thought about before, probably because I'm not that far in system development yet. I've focused mainly on story and plot, as well as character development.
So, I started thinking about the subject.
It's one of those important things, after all, and one that merits consideration because in virtually every game there's some kind of "magic" system in place. Most commonly, magic uses Mana or Magic Points (often abbreviated to MP), but some have their roots in spiritual energies or even in technology.
Game Magic Is Wide and Varied
In Final Fantasy I, for example, your spells have a limited number of uses, which replenish after resting. Similarly, in Baldur's Gate 2, spells are planned in advance and, after an 8-hour sleep, are learned ready for use the next day. And in others, like Arx Fatalis, you "write" runes in the air to cast spells.
In a number of games, notably many in the Final Fantasy series, learning new spells or skills uses Ability Points (or AP). Once you have enough AP, you can learn new magic or upgrade existing spells.
So what kinds of magic would work in Otherworld and Gaia's Dream?