They were probably artifically evolved/created by Zealians.
Don't make me laugh. The Zealians are too egotistical to go around giving others magic. Even in small doses. While I could imagine Zeal creating a new race for bragging rights, I would imagine it wouldn't last very long.
Egoistical!? Other than Queen Zeal and Dalton, everyone else seemed level headed/non-insane. The Guru's and Schala were definately not like that. And the only reason Queen Zeal was so egostical was Lavos' influence. The first time we EVER see a mystic is on Mt. Woe. It is quite probable that Zeal created them as guardians for it.
Here is where I think the Demi-Humans of CC came from: Dinopolis. My memory is fuzzy, but doesn't the game SAY they came from Dinopolis?
Doesn't this contradict your opinion of Zeal creating the Mystics? They can't be from both timelines. Dragonians know better than to mess with evolution. And Dinopolis, FYI, only brought Dragonians, which are extinct now. If Demi-Humans were from Dinopolis, I'm sure FATE would be destroying them for timeline consistency instead of keeping them in line with the Records of FATE.
Firstly: No, it doesn't contradict it. Remmber, I don't think Mystics and Demi-Humans are the same species. So Mystics being created by Zeal would be different than being evolved from Dragonians.
And guess what? If they EVOLVED from Dragonians, they would be different species. And for now, I'm going to look for a quote, or something, because I am relatively sure the game says they evolved from the Dragonians. I'm not sure though.