I left the idea of a ritual pretty plain, but that was really all I wanted to do, cuz I don't think that the ritual has any real importance other than being what makes you a pair. I based it on my own personal description of magic rituals, but not everyone thinks the same way, obviously. The ritual was a pair of circles of magical symbols drawn on the ground, interlocked in the center. These glowed blue, obviously. Each person would stand in the circle, and then after some magic stuff, a sort of chant/spell/incantation would come to the pair, and they would say this, and then BOOM your done, or die horribly. Luckily, those deaths are delayed.
I just don't know how a pair where one of them can't be heard or touched would work, even if you disregard the ritual, it seems sad...and..well boring. I mean, one person gets "Hey, my partner can only be seen through shiny surfaces, though I don't know what she's saying." and the other gets "Hey, You can't hear me... I am bored now." The mage gets no ability to do anything within the real world, because they are simply an observer. Obviously, a school for MAGES and Knights would not allow a pair that can't function fully to be in the school. If you have something else to say to try and convince me to accept the character when I am not half asleep, go ahead and throw it at me.