As founders and devout practitioners of the dominant religion in Alterion, the Masons have an obligation to guard and guide their flock. To this end, they employ Priests of varying ranks and skills to instruct, defend and discipline the citizens of Alterion. Each member of the Clergy upon order of the High Mason, must be prepared to do battle with the forces of evil in defense of the Crystal's light. To this end, every member of the clergy that has been instructed in Alterion Alchemy, is inducted into SEER and can be called away to war, should the need arise. It should be noted, however, this is typically reserved for extremely powerful members of the Clergy as SEER is already chock full of highly skilled Alchemists. It is also worth noting that while every Priest is commissioned into SEER, every member of SEER is not commissioned into the Priesthood.
Each level has the abilities of the level before it. Progress is linear branching. An apprentice can become a priest or an seer. Either of those can become a cleric or bishop.
Note that classes in red are special classes and hence not subject to inheritance, meaning that the next level does not gain their abilities. Apprentices are beginners to alchemy but anyone beyond an apprentice can consider themselves .
Summary: Initiates of the Masonic faith. Just beginning to learn about the use of divine and healing alchemy/alteria
Power: Cure [Light Heal], Esuna [Purify] , Light, Holy Mist, Detect Unholy
Apprentices are accepted into the clergy without regard for race, creed and in many cases religion, as Masons generally belief that all religious belief stems from theirs. Unlike the positions higher in the clergy, potential apprentices need not pass before The Crystal or the High Mason. Priests, and higher clergy, are skilled at discerning lies and intention. As apprentices are bound to spend a lot of time around a lot of priests and other clergy, for extended periods of time and in extreme circumstances, no other measure is necessary.
The first year of a disciple's apprenticeship is spent in extreme poverty. This teaches them hardship and how to endure the pains of the body. Many typically operate as servants to Priests and assist in various events, rites and rituals. It is during this time that the apprentice begins to understand his role as a cog in the machine that is the Masonic Faith.
Though only a single year is required before passing into the next phase of apprenticeship, it is not uncommon for some disciples to continue on in this state for years more, mastering their alchemic arts.
The next year of apprenticeship teaches the apprentice wisdom and humility. They learn wisdom from constant interaction with the priests. The main principles are that though one must feel their emotions they must not act upon them without The Crystals blessings.
They learn humility by committing themselves to chores. The cooking, the cleaning, tending to the wounded, repairing the temple as well as private residences, helping the citizens harvest their crops and so on.
In the third year, the disciples are brought before thethe Crystal and begin service beneath its Light. Their healing and holy alchemy is put to the test and those that do not pass, must repeat their apprenticeship.
Summary: One step up from apprentice. Begin to learn more about the advanced healing alchemy, deals with home-visits to the lower nobility , and blesses adventurers.
Power: Cura [Medium Healing], Bless Item, Shield of Faith, Speak with Dead, Calm Emotions, Find the Path , Esunara [greater purify; cure disease]
Summary: Budding diviners taught to prophecy, to read portents and omens, and to remote-view—often through scrying crystals. Used by local Poor Sons to sniff out criminals and report crimes, though never reports future-crimes.
Power: Prophecy, Remote Viewing, Empathy (read only), Discern Intent 
Summary: One step up from priest. Can begin dealing with evil and the undead, able to turn them away, to bless whole houses instead of just items.
Power: Curaga [Heavy] Healing, Bless Land, Repulsion [Evil], Spiritual Weapon, Remove Status Effects, Discern Intent , Gate, Esunaga [Cure Disease—Supernatural]
Summary: A righteous knight of the Crystal. Their divine and holy powers focus more on the offensive and aggressive than on the defensive and palliative.
Power: Holy Sword, Scar Evil, Discern Intent 
Power: Curaja [Critical Healing], Exorcize, Holy Aura, Tongues, Dictum, Discern Intent , Find the Path 
Any rank up to and including Diocese is able to act as Inquisitor as will. Inquisitors are able to enter into any crime scene or lawful disturbance with a judiciary rank comparable to a Justicar, and the crimes they begin with may not necessarily end when the primary suspect is caught.
Most of the time Inquisitors focus around issues of religion and radical defectors but they also deal commonly in secular cases and specialize in advanced interrogation and anti-terrorist tactics.
The High Mason, known as the scion of the Crystal, the Creator of All, also holds the epithet of 'Most High'. It is an title that holds a great deal of weight in all branches of Alterion's faith militant. In order to earn the prefix of 'High', an Inquisitor must have spent five years learning the rules of his station and then request a meeting with the High Mason where, over a period of days, the applicant will be tested on the strength of his or her moral logic, spiritual intelligence, legal knowledge, and physical capability.
Upon passing the Inquisitor then returns to work for an unspecified length of time, while a Seer (not to be confused with the militant Alchemy group SEER) records their every move daily and they are sequestered every three months to be questioned by a High Inquisitor inside the Justicar as to their every motive and intention.
The reason that these evaluations are so stringent and demanding is that High Inquisitors are exempt from almost any limitation of Masonic law during the extent of their investigations and operate as independent agents, beholden only to the High Justicar and High Mason.
Summary: The highest rank of the Masonic religion, below the High Mason. There are only 5 Arch-Masons.
Power: Banish [Exorcize (2)], Divine Alchemy, Raise [Resurrection (2; weakens after every time), Soul Bind, Discern Intent 
NOTE: I borrowed heavily from Carlos/Supernal's article on Gaianism: the Clergy.