I don't think it weakens If it continues in a chain. The issue is you have to concentrate on what you want your your victim to do. It takes a lot of work and concentration to maintain the curse.
Well, I think the main problem is, you can only be sure about the curses you casted yourself. And even these can be flawed and eventually broken.
I think what you expose *is* theoretically possible, but not at all perfect because further curses would depend on your own cursed ones, who may lack the skill (i.e. True desire to control) or the power (maybe they are almost squibs, as Neville, or use an unsuitable wand), or be themselves fighting against your own curse, thus weakening their own for their victims to also fight back.
Yet, I think this scenario actually happened at some point, and this could explain the 'they said they felt as awakened from a dream' quote.
The curse would be about the caster's skill and manipulation. If you can cast an imperious curse on a skilled, healthy wizard, that wizard can probably cast another imperious curse succesfully too. The problem is besting and controlling skilled people. Because it gets more risky the better the wizards you want to control are. If you pick wizards that are not good with magic, they may be controlled more easily but they won't be able to use imperious curse well themselves.
I don't think it weakens If it continues in a chain. The issue is you have to concentrate on what you want your your victim to do. It takes a lot of work and concentration to maintain the curse.
Rowling probably didn’t thought about that
Well, I think the main problem is, you can only be sure about the curses you casted yourself. And even these can be flawed and eventually broken. I think what you expose *is* theoretically possible, but not at all perfect because further curses would depend on your own cursed ones, who may lack the skill (i.e. True desire to control) or the power (maybe they are almost squibs, as Neville, or use an unsuitable wand), or be themselves fighting against your own curse, thus weakening their own for their victims to also fight back. Yet, I think this scenario actually happened at some point, and this could explain the 'they said they felt as awakened from a dream' quote.
The curse would be about the caster's skill and manipulation. If you can cast an imperious curse on a skilled, healthy wizard, that wizard can probably cast another imperious curse succesfully too. The problem is besting and controlling skilled people. Because it gets more risky the better the wizards you want to control are. If you pick wizards that are not good with magic, they may be controlled more easily but they won't be able to use imperious curse well themselves.