Divine Patrons and Excommunicated Spell-casters

Every divine caster draws their power from one or more of the Nine. There are no clerics of a cause or of nature in the abstract.
Divine casters are normally expected to uphold their divine patron’s basic precepts. A divine caster who strays can have casting and mana replenishment difficulties raised by one as a warning until they make recompense.
A divine caster that has truly fallen off the wagon can have difficulties raised by two, but the Nine either cannot or will not remove magic entirely once given.
A divine caster in the dog house with his/her deity can turn to another deity to petition for a new patron but this typically involves a difficult quest though some deities are eager to “flip” their rival’s followers and make the process fairly easy.
The Nine are surprisingly lenient for their followers missteps, see the lore article Excommunicated for details.
It makes a great deal of difference to a character's background whether he is a theurgists or a favored souls, but for mechanical purpose, there is almost zero difference.
Favored souls and theurgists regain mana the same way, they have the same spell casting traits and roll against the same difficulties. The sole mechanical advantage favored souls have is that they cannot become excommunicated under any circumstances.
Having the Pantheon as a Patron Most Scarterrans worship most or all of the Nine. Most divine casters will offer occasional prayers to additional deities beyond their patron but value their single patron above all others. A rare few divine casters draw their power from all of the Nine collectively. Mechanically, these casters cast spells the same way every other divine caster does, they just have to strive for balance between all the Nine rather than dedicating themselves strictly to one of the Nine’s values and precepts.
While it is possible to worship more than one deity but less than nine of the Nine, the only way a pantheon follower can wield divine magic is their piety is relatively evenly dispersed between the Nine collectively