Well, to start with, I would have to use charcoal when I wrote her. After she got over not being Branded by Adanvari, Jaida would be thrilled to be Branded by Largessa, to have a monumental fate that would ensure her a fine death. And to have Helene in her head from nine, before she even awakened to her power as a mystic? You think she's axe-crazy now? HAHAHAHAHA.

She would have gotten along very well with Helene, I think. As much as it's possible for Helene to get along well with anyone. Likely, that would still entail wanting to kill Jaida.

Likely, Jaida would run away from the Abbey to train herself (occasionally picking knowledge out of Helene's head) as a slayer. Joanna would still abandon her to the sisters to seek a place at the cathedrals of the holy city of Sophia Nova, and Jaida wouldn't really get along with any of the three sisters at Arethusa. She would eventually overhear Helene's plans to kill Largessa and would decide to kill the goddess so she could taunt Helene with it. You know, before Helene killed her for doing so. Jaida would likely think it worth it, and would probably enjoy fighting Helene to the death. Meanwhile, Battle For the Sun would be an entirely different story on account of the Dragonians still being around.

I think that about covers it?