Just a note on summoning...
Summoning, far as I know, is an allagan art.

The Allagan were actually quite... Adept at binding and controlling entieties. Ultima Weapon could absorb and use primals as fuel, there is what you realize at the end of Turn 5 and there is, also, the possibility that Midgarsormr was dragon of near godlike power (though not a primal, still a living beast) enslaved by them.

Perhaps there is more to summoning than we notice.