Okay, so Feedback.. What would happen, is that when someone demenses into a city/commune, the.. Warrior guild, since both Cities and both Communes have one, are able to activate feedback, which will last for.. maybe 10-30 minutes and during that time, energy will be sent back along the link between the Demense and the person bonded to it. It would give afflictions, like making them dizzy, stupid, and some other mind afflictions, and it will also sap at their mana constantly, until they have none left, they dissolve the demense (the whole thing.. you can't just dissolve one room, can you?) or the Feedback is turned off, by either running out of time or someone turning it off prematurly.
I'm not sure what the cost would be.

....... eh, I don't know about that one.

5,000 power, and it's any demesne, not just an enemies' demesne.

Eh, I don't like it.

Yeah, I'm not crazy about it either, sounds like just an irritating thing that wouldn't work all that well. Although, it would probably effect aquamancers the least, I get 1000 mana from twirling staff, and I could just sit in sweetfount

What they should do is make this a village-in-play discretion power.

Every type of demense, except the native one.. like, it would attack a flooded, forested, or tainted forest demense in Mag, but would leave Taint alone..

I'm jealous of aqua staff twirl.

As to the demesne thing... eh, I know I'm biased but it's either going to be worthless, or utterly stop enemy demesnes. A simple power shouldn't be able to do that.

Staff twirl isn't very good, the balance time is really bad.

Mm. Geb uses it a fair bit though doesn't he?

In any case, it's better than Hartstone twirl, which does...nothing.