We should aim to identify what is influencing her, and incapacitate her until we can deal with the problem.

[Easier said than done, but at least there's a good sized group and thus far the Circle members have shown themselves to be reasonably competent. If they plan well enough, they can probably take Ilde down without seriously hurting her.]

Perhaps we can wear her down and then try to render her unconscious. If our interference happens to draw out the true culprit before we have to knock Ilde out, so much the better. We can take out who or happens to be controlling her in a less gentle way.

[And by "less gentle", she means shooting it full of arrows, smashing, and otherwise taking the culprit out beyond recovery.]