The cleric is an advanced class of the Magi can function as a tank for a party, providing decent defence and having access to very powerful area of effect heals, 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 reccomended stat.
They have access to the standard level 25 Magi skills as well as 2 Unique skills,
Life 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.