Creating a unique and interesting magic system with at least a hint of originality has always given me trouble. I believe I have a central idea which will work, but I am looking for some feedback to both expand it as an idea, and to highlight potential pitfalls or opportunities it might present. Essentially wizards must be created by killing one of a set of twins in the womb. The living twin would then be able to utilize their siblings spirit, this being the source of their magic. I envision this as a highly ritualized procedure carried out by either established arcane organizations, or by arcanists in the employ of governments. For the magic itself I know that I wish to invoke the twin bond strongly enabling wizards to see through the eyes of their spirits and the like, perhaps even to stray into some traditionally ghostly powers such as possession and telekinesis. I do know that I wish for wizards to remain vulnerable and steer clear of them being unbeatable by ordinary men. I do not believe I want it to be possible for a triplet to invoke two spirits, etc. Thoughts appreciated.