Concentration represents a user of magic focusing his talents on the study of magic from one particular otherworld. Mechanically this is represented by an ability like "Concentrated on Spirit World" or some such. This ability is free to take for any character who has more than the basic level of commitment to some magical tradition. That is, lay members, spiritists, and such people who merely attend religious services or the like will not be concentrated. But anyone who has taken the next step into some magical tradition may. Some sorts of magic may require a certain level of concentration to be proficient with that sort of magic.

This ability counts as a flaw as well as a broad ability. That is, it counts as a penalty when the character deals with magic or effects from any otherworld in which he's not concentrated. But it also counts as an augment to the magic and other effects that he uses from or are assoicated with the otherworld in which he is concentrated. Basically such concentration creates a blind spot for other forms of magic while enabling the character to be proportionally more effective in their own form of magic.