There are orbs everywhere, holding peoples spirits and releasing them when it’s been too long or too much.
The orbs are fragile, not like glass is fragile, but fragile like metal. Strong to a point, get it hit enough or try and bend it when it’s too cold and it’ll change.
And the orb isn’t meant to change, only the things inside the orb are meant to change. If the orb and the spirit both change there’s too much. The mechanics of it are hard to explain but throw in some words like ‘overload’ or ‘critical mass’ and it sounds logical.
The spirit has to find a new orb but there’s no logic in how that happens, just hope and magic.