You surprise me :)
Do me a favor and explain it to me, as I'm not very bright :D. I did everything again as you said: a level 1 hero with 8 Angels attacks 8 Devils, and the numbers are:
Angels attack Devils without a hero, damage 193-314
Angels attack with a hero, but without the ring, damage 193-314
Angels attack with the ring and a hero, damage 193-314
The only different damage occurs when
Devils are in defense, damage 154-252
Angels are happy on their turn, and Devils are not in defense, damage 242-393
I took screenshots, but I can't upload them yet.