...is there no limit to summons? I realize I was actually assuming I couldn't use a summoning spell multiple times for the same character, but maybe that's wrong. I usually try to keep a single, most powerful summon for each character that has one (and for difficult battles, I've used summoning scrolls for other characters).

I considered a few times trying to see what would happen if I summoned more, but figured it'd make the game too easy, anyway. A lot of the summons are quite strong and they have a lot of health.