Someone already said on other thread that it act like Sacrament, its Additional holy damage, which means an additional elemental damage line, probably based on the total damage (pattack or mattack) which means at Lv 5 it would add a new line with 50% of the char attack.
Now for my doubt, does it add the affected char attack or it is based on the caster attack?
But since when it is cast by the char when being used it break that limitation, i would guess Kagura Dance effect is based on the affected char, not based on the caster.
I will try to test, not sure if it affect zombies, otherwise i will have to wait a friend to test it.