This. She was never explained, never given a motive, never developed... She was just there, like so much of FFTA2's "story" was. Really, people blame FFTA for being bad, but at least it had a followable plot and a 'villain' (though the nice thing about FFTA is that it's really difficult to say who the villain was. Even Remedi isn't really one). FFTA2's story was just laughably bad and random. I mean, WTH? I finished the game and still can't remember for the life of me what it was about. Ilua was just the final drip that killed the game for me.
Or no, scratch that and make FFTA2's final boss the final drip. Pure tacked-on-ness. People complain about Necron? Meet the Final Boss who has no name of FFTA2 who is even less explained than Necron and has no lines or background at all. At least Necron has the theory of being the Iifa Tree's Soul Core going for him. But TA2's final boss? Niks, nihil, nada. He truly was a random monster that just showed up. Compared to him (?), Necron is a deep and developed character and villain.