Here are my calculations:

1 Archangel vs 1 Archdevil (the archangel attacks first)

I am not taking the heroes' stats into account, or they are equal.

The angels' attack is 2 higher than the devils' defense. A difference of 2 gives a multiplier of 1.1

attack: 1*50*1.1=55.
counterattack: 1*36*1.05=37 (after rounding down) - 1*66*1.05=69

in total, after the 1st turn, the devils have 144 HP left, and the archangels have 151-183 HP. The calculations show that the angels need a stable 4 attacks to defeat the enemy, while the devils need 4-6 attacks to kill the enemy. In general, if the archangels attack first, they will definitely win; if the archdevils attack first, they have a chance to win... The average damage should be at least 55 for all their attacks, while their actual average damage is 53, i.e., the archdevils' chance of success is slightly less than 50% in the case of their first turn. Their initiative is the same, i.e., 50/50, which means that the archdevils are more likely to go first. In general, the archdevils have a chance, but it is much less than the archangels'. The simplest possible calculation gives an idea of who will win... In reality, it is not quite the same. If you take the heroes into account, the archangels' position becomes even more advantageous. The demons' attack and the humans' defense compensate for each other, while the humans' attack is significantly higher than the demons' defense. Usefulness in battle is another matter, which cannot be calculated, but is verified in practice.

P.S. I have rechecked all the calculations, but errors are not ruled out (although unlikely), I apologize in advance.