Double battlefield enchantment?

[Isokron]

Assume that both sides in a battle casts the same battlefield enchantment (say mists of deception or relief). Who get the benefits from the spell, both/none/first caster/last caster/random ?

[lch]

There's one icon to the left of the battle screen for active enchantments, one to the right, corresponding to the side of the nation, and both work according to the spell mechanics. So if it's a battlefield enchantment that will target every enemy unit, it will do exactly that, if targets ALL units, including your own, then it will do exactly that and not stack, AFAIK.