The user is able to summon and make a servant of a astral entity. These energy beings live in the Astral Plane and sometimes visit the Earth.
The user can either convince the entity to stay (usually by an "allowance" of P.P.E. that feeds the creature), or can bind it to the domain by force. In the second case, the entity will be a reluctant slave, often eager to betray, or escape from its master. In the former case, the entity will be "fed" a steady trickle of P.P.E. in return for its services. Most entities will be moderately loyal, although they will rarely fight to the death for their master. Role-playing the interaction between an entity and its summoner can be fun, and it may also lead to more loyalty.
10 for a lesser astral entity, 20 for a common entity, and 40 for a greater entity.
Bound Astral Entity: In this case, the creature is summoned and then magically or psychically bound to the domain. The enslaved entity cannot leave the area, and must obey the instructions of its new master to the letter. Summoners who bind an entity must be very careful with their words, for many entities will try to twist the meaning of their commands for their own benefit.