Explanation of Bathraz Summons
He basically uses abilities to get charges. Then spends those charges on special skills.
His abilities will say stuff like “will summon one weapon” and then during his turn on the left side of the screen (or if you press the menu button to check character buffs in battle) you’ll see he will have x amount of summons (based on the amount of abilities you’ve riser) up to three at a time.
Then he has that one move where your can use all of those to attack one time (summon attack I believe).
In other words out of the box he lacks any skills that actually uses his summons, but later you can learn a few skills that eats the stacks for an effect, earliest one is summoned strike or something like that, eats all the stacks for a (All) attack that increases in power per summon.