Dimensional Protectors Guild
Not the Green Lantern Corps, I SWEAR.
Planar cartographers and theorists on Earth once speculated that the existence of so many planes of reality could someday become... problematic. With so many realities co-existing, the best metaphor for the theorized result is that the planes would begin to chafe. This was a matter of some concern, so an organization was developed with the original intent of investigating the theory. As the DPG grew in power and standing, the organization moved from its base on Earth to a dimensional nexus for ease of access to extraplanar territories and, hopefully, allies.
To seek out new life forms and new civilizations.... no really. Part of the purpose of the DPG is to document and learn from other planes. The other purpose is to help ensure stability among the planes and their inhabitants. It is not uncommon for DPG members to be assigned to planes in the midst of large-scale intraplanar conflict. In this case, their purpose is two-fold. They must bring back what information they can, and also assist in the political stabilization of the area.
Only rarely do DPG members become involved in interplanar disputes, though it is not unheard of. This is viewed as a natural expansion of the goals of the DPG, and members who take on such tasks voluntarily do much for their reputations within the organization.
Senior members are always in charge of recruiting prospective members, as they have proven their judgment and dedication. DPG members are recruited from any and all monitored planes, with many such members coming from Earth. Most are not mages when they are recruited, as Earth has not historically proven itself to be a viable source of powerful magical talent.
Prospective members tend to be people who could disappear easily, people who have severed ties with friends, family, etc. If it has been determined that the prospective member could be removed from the monitored plane with minimal difficulty, they are followed and watched carefully. If the senior member trailing the potential judges that his or her charge possesses sufficient ability, judgment, and emotional stability, the senior member is authorized to make first contact at his or her discretion.
Potentials, should they accept the senior member's offer, are trained in the dimensional nexus used by the DPG. New DPG members are temporarily apprenticed to a senior member, and for most this is the very same member who recruited them. Occasionally this is not the case, but new members must always have a sponsor to ensure the well-being of the recruit, as well as the quality of his/her education.
If their talents lie in physical combat, recruits are given whatever combat training suits them. Most, however, become mages. When the final choice is made to become a full member, the aura of the new member is altered to ameliorate the interplanar "chafing" that was the DPG's original problem. It's perhaps most instructive to think of DPG members as interplanar ball bearings that keep everything moving smoothly. The alteration in the member's aura often manifests itself in the form of some minor physical change. Shakti and Cardinal Messiah, for example, experienced a drastic change in hair color, though they were otherwise unchanged.
They are expected to work "in the field," and are therefore stationed on monitored planes to investigate other cultures.