Confinement

Confinement is the ancient wizarding act of summoning a shadow from the Nethereal Plane and binding it to your command. The procedure is dangerous, and must be done with caution and preperation; a summoning circle is needed, as well as incenses, rosemary, and silver wards, which protect the wizard while it summons the shadow. Most importantly, the wizard must know the shadow's true name, which is used as a way of picking it out from the millions that inhabit the Nethereal Plane, and then controlling it on the Material Plane. After reading a summons (a procedure that takes no less than 10 minutes, and sometimes up to days, depending on the power of the shadow) the shadow rises from the Nethereal Plane into the summoning circle, and is bound to your commands (as per the wording of the spell find familiar). Dismissing the shadow requires less time, but still needs the summoning circle and other items of protection. A faulty dismissal or summoning results in the the shadow breaking free of its bonds and having the opportunity to attack and perhaps kill the wizard. This can also happen if the shadow finds itself in an area of complete darkness, where the Nethereal and Material Planes overlap, and it can throw of it's bindings and escape (once again, perhaps killing the wizard on the way out).