Cleric

Clerics are spellcasters devoted to their god or goddess, able to call upon both holy powers and considerable martial capabilities to act as protectors of the faith. On Akiviras, clerics serve as missionaries, church-tenders, and spiritual guides to peasant and lord alike. Many clerics choose the adventuring life in order to combat rising evil, raise money for a new church or holy place, or simply as an excuse to travel and spread the word of their divine master.

Attributes

Though clerics in their churches typically wear white or sandy brown robes, they are capable of wearing even full plate mail on the battlefield. Their weapons are limited by their clerical vows, meaning only bludgeoning weapons and those that don't shed blood are permitted. These vows serve to reinforce the cleric's position as a slayer of monsters and undead, rather than men. Evil clerics also hold to this rule, as a twisted facsimile of their good counterparts. This parallel strengthens the evil cleric, as negative energy is in essence a twisted facsimile of positive energy and demands the same of its wielder. In combat, clerics are almost as powerful as fighters, having a d8 hit dice and the second most favourable hit tables of any class. In terms of alignment, clerics must be at one end of the alignment spectrum; they cannot be neutral in any capacity. That said, they can be lawful or chaotic good as well as lawful or chaotic evil.
However, the cleric's most potent weapon is their spellcasting. Unlike magic spells, divine spells must be prayed for each morning by the cleric, meaning that they have access to their entire spell list right off the bat rather than having to slowly build up a collection like magic-users do. Clerics also possess the ability to 'turn away' undead and evil creatures, driving them off with the holy warding power of the sun (or commanding them into service with the alluring embrace of darkness). This ability requires the use of their holy symbol, but it makes clerics very useful indeed in dungeon explorations.
All clerics must have a religion to which they have dedicated themselves. For most human clerics, this is Celeanism, though some may choose the increasingly popular Sliverism for various reasons. There are no gameplay differences between the sects, though Celeanism favours lawful clerics while Sliverism, by it's rebellious nature, favours clerics who are more chaotically inclined. Nonhuman clerics may worship any of their pantheon's gods or goddesses, including half-orcs, though they typically worship their gods in secret to avoid retribution.
When a cleric achieves 8th level (Patriarch or Matriarch) he or she automatically attracts followers if the cleric establishes a place of worship — a building of not less than 2,000 square feet in floor area with an altar, shrine, chapel, etc. These followers are fanatically loyal and serve without pay so long as the cleric does not change deities and/or alignment. Upon reaching 9th level (High Priest or High Priestess), the cleric has the option of constructing a religious stronghold. This fortified place must contain a large temple, cathedral, or church of not less than 2500 square feet on the ground floor. It can be a castle, a monastery, an abbey or the like. It must be dedicated to the cleric’s deity (or deities). The cost of construction will be only one-half the usual for such a place because of religious help. If the cleric then clears the surrounding territory and humans dwell in this area, there will be a monthly revenue of 9 silver pieces per inhabitant from trade, taxation, and tithes.

Spellcasting

Whether a cleric is good or evil determines whether they draw their spellcasting power from the Positive radiation emitted by Akiviras' sun, Ceranderus, or the Negative radiation spawned by the black hole that serves as its counterbalance. The two energies destroy each other if they touch, meaning clerics who wish to draw on its power must keep a source on hand. Good clerics drain power from the light of the sun, while evil clerics draw energy from darkness, leaving only a hazy semitransparent grey blur that slowly fades. Devoid of a source of energy, clerics cannot cast spells or turn the undead, severely diminishing their power and leaving them vulnerable. Thus, a good cleric in total darkness and an evil one on a sunny day would be equally depowered, although evil clerics generally have the advantage in such matters due to their ability to draw upon their own shadows. For evil clerics, the amount of energy they can pull from a given source (which affects the maximum spell level they can cast with it) depends on the relative darkness of the area in question, and the amount of continuous darkness that can be drained. Good clerics require the sun to cast most of their spells, but can cast spells of up to 3rd level by draining the positive energy that exists within living beings, as well as certain sources of light or heat. Fire, therefore, is a popular choice of draining, and many clerics will venture into a dungeon with a backpack full of flowers or grass clippings to drain during a needed moment.
What spells use what charges is a matter of the spell itself. Positive energy charges any spell that deals with healing, fortifying, creating, revealing or protecting. Negative energy is everything that destroys, slays, hides, obscures, weakens or harms. 
Spells that are not reversible, such as Command, can be cast by either class using their respective energy sources. Spells that are reversible, such as the Cure/Cause Wound spells, must be cast with either positive or negative energy depending on the cleric's alignment. As a rule of thumb, the normal version of the spell uses positive energy, while the reversed version uses negative energy.