I can already see the many possibilities this will give you in terms of lore and gameplay. Two "saikos" would be an interesting spin to the story and I'm sure we'd all love to see what your plans are with this game.
Here's to wishing you all the best with this game: it's got promise and it keeps on delivering on it!
EDIT: Please let the other one be her twin... I don't know why, just sounds awesome...