Fire and Blood

There are a lot of stories about people reborn into a fantasy world but most such individuals seem to be young, inexperienced and forced to start from the bottom up. But who attempts to summon a nobody, expending vast magical power to do so? What if there is an effort to summon a champion of the celestial host and strip them of their free will, binding them by their True Names only to be foiled as they vacate themselves to follow possession by another? What if the one summoned from something approximating our own world is a veteran in her thirties who now finds herself in a form alien, powerful, but far from invulnerable? It involves a whole lot of fire.