FASA Games, Inc.

If 2 elementalist cast Earth Darts on a target will the effect be added

-2 Physical Armor + -2 Physical Armor = -4 Physical Armor ?

Firstly, please change title for "[4ED] Stacking spells" or something that will be more specific.

Secondly, they don't stack and only the highest penalty aplies and if new spell is cast, it only gets duration extended. Or rather exchanged for that of a new spell.

Example:

If you have Earth Darts cast on target with extra 2 succeses (-2 PA, 6 rounds) and you later cast another with the extra threads but not successes (-6 PA, 2 rounds) and the old spell is in effect then you got -6 to PA for 2 rounds, and then reverts to -2PA for the rest of duration of first spell.

That is how I would do it.

Alien and etherial are correct on how to handle this.

Hahahaha, Alien but it is indeed correct translation from Polish

Mod: Title changed for clarity.