another crazy thought
what about giving them a happiness bonus for a couple of turns, when they kill a unit, you could differ humans, elves and dwarves.
Happiness would be caused by trophies gained from the killed units (maybe ears, teeth or heads).
each killed unit would give happiness for like 2 turns and the bonus stacks, meaning that nif you kill 5 units you get 10 turns happiness and it is prolonged by 2 turns for every unit.
with the 3 races you could get up to 3 happiness through this, may sound much, but you would probably have to be at war with 3 civs for that.
additionally if you have one of those "Ear Ressources" units produced in the capital get the according Slayer Promotion.
or maybe a national wonder for Doviello thats grants those bonuses.
then there should really be a Bloodlust Spell, avaiable to Doviello and CoE at Divine III or maybe a minor version on II.
The Minor Version could give the whole stack +20% Power for 1turn, maybe -10% Defense too.
The Big Version could give ONE unit +50% Strenght for 1 turn and heal the unit for a tiny bit, at the end of turn the unit gets something like 5-25% Damage. (That would mean the unit gets a temporary boost in strenght, during which it feals no pain, but when the boost is over it may die, depending on how severe the damage taken was (seems fitting to the theme))
instead of the 50% bonus i think a direct bonus to the Strenght Points would be better( like Heroic Strenght)
the reason is that 50% could be overpowered with the really strong units, but otherwise it would be to weak for a lv III spell
mfg
Mavy