In the FAQs, there is (or was) a question regarding moving a constant Area of Effect power. The general rule was that it shouldn't be allowed, or, if allowed, it should be expensive. What about powers that have no range? Can you establish an AE centered on the character (like Darkness) that moves with him? As an example, I have a character who is able to create an energy-damping field around himself, which I've simulated with a weak Drain:
1D6 Drain from STUN and END at once (+1/2), return 5 pts / min (+1/4), AE 12†radius (+1-1/2), selective (+1/4), continuous (+1), penetrating (+1/2), 1/2 END (+1/4); can only activate one instance of power at a time (-1/4)
The assumption was that this power's area moves with the character since Drain has no range. Whenever a new target entered the field, an Attack Action would be necessary to affect that individual because of the Selective Advantage. The Limitation for only activating one instance at a time was intended both to simulate that the field is either on or off and as a balancing idea (if you could stack them up, it becomes abusive).
Would this be legal, or would you consider it constrained enough not to be abusive? (In this case, I'm the GM, and I think it's borderline, but a second opinion would be useful.)
The original Q&A is quoted below for reference:
Q: Can a character move a Constant power that covers an area (either because, like Darkness, it inherently affects an area, or because the Area Of Effect Advantage is applied), and if so, what rules apply?
A: Once established, a Constant Area Of Effect effect generally can’t be moved (general exception: Darkness used on one’s self, per 5E 96). It is possible to “attach†an effect like that to a target with Usable As Attack (see elsewhere in this Rules FAQ), such that it would move when he moved, but that’s different from allowing a character to “sweep†(little s, as opposed to the Combat Maneuver Sweep) an Area Of Effect across a broad swath of ground.
Assuming a GM wanted to allow such a thing, based on a reasonable special effect and a judgment that it wouldn’t unbalance the game, it would have to be expensive. As a starting point, it would probably be at least a +1 Advantage, the same as the Usable As Attack method mentioned above. It probably should also be No Range by default, but with the possibility of adding the Ranged Advantage.
Moving the power would constitute an Attack Action, and the GM would have to decide how many inches the Area could move per Phase (and whether it could move in three dimensions, or just along the ground). One possibility would be that a moveable area moves as fast as a standard human (6â€), and that the character could up to double that rate for each additional +1/2 Advantage (7-12†for +1/2, 13-24†for +1, and so on). Another would be that the Area can only move, say, 1â€, and each +1†of movement costs 5 points. Of course, you could change these values up and down to suit yourself.
A moveable Constant Area Of Effect would definitely be a “stop sign†power.