My guess is that the rite of passage tries to hypnotize children into weakening their powers for their own safety as they probably do not have the control needed to supress the cat that would kill them. Said cat created by their own power. Or maybe that cat is just attracted to weak (as in control) cantus users that release too much uncontrolled cantus.

You noticed the metal, I noticed the glasses. Red/pink glass sunglasses, with complex form perfectly adapted to her face. Seems to me it requires some tech to manufacture those. More oever, they're not your traditionnal (and useless if not dangerous for the eyes) shade sunglasses, they seem to specifically filter part of the light spectrum, like UV sunglasses...