I think the Aporos could have been a school dedicated to wards and other similar anti-magic defenses. Effectively the same as using a chorae, but not necessarily the same, mean that there could have been many different side effects other than salting and no-magic objects.
They could have specialized in no-magic fields, like the Anarcane ground, and had many objects, such as armors and weapons, that protected from sorcery effects. The chorae could have either been the penultimate achievement, or simply a cog in the wheel.
Would the Aporeti be sanctioned by some diety, similarly to the Psuke?