WITCHES, DRUIDS, PRIESTS, AND MAGES:

This file explains the differences between them, and where they get
their power from.

WITCHES: During a witch's consecration, she tries to get in contact
with one of the Four Lords (presumably the one most closely aligned
will answer).  Once contact is made, the witch will promise said Lord
his/her soul on the occasion of his/her timely death in exchange for a
gift of power from said Lord.  The Lord, if he/she finds the new witch
acceptible, will grant them one power, and seal the bargain with the
gift of a familiar, a demon/devil/etc possesing an animal; this allows
the witch to regenerate mana points, and will also grab the witch's soul 
upon his/her death.

DRUIDS: This is a class much like witches, but there is no bargain
made for their souls.  Druids are exclusively Gaeic, and get their
power from a companion, which lets them regenerate mana points.
Companions differ from familiars; familiars are demons/angels
possessing an X; companions are an X that chose, according to Gaea's
will, to ally themselves with the druid.

PRIESTS: The priests are direct worshippers of the ninth-level deva
(aka, The Gods).  They get their power (i.e., regenerate mana)
directly through their prayers, at some fixed rate nightly.  They
don't need familiars.  They can use the spells aligned to their gods,
and undifferentiated (i.e., clear) spells at normal cost, but they get
penalized for using spells not aligned to their gods (i.e., they cost
more to cast).

MAGES: mages don't make deals with their souls to get power.  They
regenerate mana points through a link to an Orb.  These Orbs draw
power from the Six Underplanes, and are each aligned to a single Lord.