Last time I was fighting and had first move - enemy shamans started with like 50/65 or 33/65 Adrenaline - I think they cheat!
About Runic Armor, from game files:
The armor's strength depends on the Talent Runes of the hero. The player's dominant Rune determines the bonus:
Might Runes: +30% Physical resistance
Mind Runes: +30% Resistance to Poison and Fire
Magic Runes: +30% Resistance to Magic and Astral damage
If the hero possesses more than 20 of the same Rune, then the armor's resilience will be increased by another 10%.