The cleric is an advanced class of the Magi can function as a tank for a party, providing decent defense and having access to very powerful area of effect healing spell. They also make a great support class due to their ability to heal other players spirit and health bars. Willpower affects the strength of their healing spells and so is a recommended stat.
They have access to the standard level 25 Magi skills as well as 3 Unique abilities,
Unique Abilities: EditLife is an AOE (Area of effect) heal spell that heals all nearby players, it then buffs all of the players healed with a heal over time effect. Heal is the most powerful healing spell in the game.
Starlight is a skill that regenerates spirit for all nearby players but not the cleric who casts it, it then provides a small heal over time effect to the affected players spirit. It currently provides the same buff to monsters and enemies.
Saving Grace is an instant cast healing spell. This can be cast onto all players including yourself. Being partied is not required for the heal to effect other players. This can even be cast onto enemies for no healing but will still put the spell on cool down and spend the SP. Maxing this ability only increases the Vital of the spell making it more potent at 3rd level. This spell like all spells in game ignores line of sight in order to cast onto your target. This spell has the range of 10 square tiles.