I increased my defense and equally handicapped the two bosses. Both “Missed” on their physical hits, but given the mana gained from my multiple combos, each fired their AOE spells. Wiped out everyone except one hero leaving her with 5 hps. I am wondering about either sides ability to simple Fizzle (failed).
AOE moves either hit all or miss all. It’s poor game design, but that’s how it works.