In Creation's Heart: An Epic YA Fantasy Adventure - Roots of Creation, #8

The playing field is level, or so everyone thinks... After a costly victory against their enemy, Jak now possesses her brands, and one of the two Pillars of Eternity. Yet Cain is still as powerful as she, if not more-so. And he still retains the other Pillar. Demons are gathering throughout the land, and if Jak can't do anything to stop it, everyone and everything will burn. But whether they win or lose, this will be the last confrontation.
Together with Naem, Seph, Skellig, and all those who have helped her in the past, Jak must face Cain for the last time. That final battle and more in this, the eighth and final book in the Roots of Creation series.