Why did Misery make Ballos create the demon crown?

I think this might have been answered somewhere and I'm a idiot, but discuss.

 

She believed that it may reduce the amount of magic that Ballos has and would allow him to gain control of his magic.

 

Misery desired more power, so she forced Ballos to create the crown. She was subsequently cursed by it. Misery has never shown any inclination to be helpful to people unless they had already done something for her, as was the case in her freeing you from Ballos' room. And the reason Ballos' magic went wild was because he was insane, not because of him having too much ability. If that were the case, he would have been destructive from the beginning, it was not until he was tortured that he finally broke.

 

She believed that it may reduce the amount of magic that Ballos has and would allow him to gain control of his magic.

No. She obviously wanted to control his magic for her own use, because Misery is, by appearances, the weakest magic user of her family.

Or hey, maybe she couldn't use magic at all and the crown is the source of her magic, maybe she got what she wanted at the cost of servitude. She wasn't floating at that end cutscene, but rather standing on her own two feet.