This class is the main support class of the game and are the second supporting Unit to be introduced after the Ranger. They can use healing abilities and do light damage (Effective against any dark type revenant.) They are arguably the most useful class in the game due to their damage buff (Zeal) and their ability to heal. Though it is possible to beat the main Game without use of them at all especially on Casual and Normal difficulties (though Game+ may be a little more difficult to achieve the same results with).
Their skill tree is rather simple compare to the other classes, resulting in limited applied tactics outside of Zeal and Heal. They are also the only unit with a square range, and can reach a full 2 squares round them. They can have their skills leveled up to increase a chance to add blind to all attacks, but this remains their only bonus. Zeal is the slowest technique within the game, though their other techniques are rather quick to apply.
Their interface within a battle also reflects their limited tactics; they have only the ability to "Heal", "Attack" and do both. They cannot single out a foe to attack as a result like all the other classes (such as attacking the strongest, weakest, etc), though have area attacks instead.
They are limited in terms of attack potential overall and have to be placed with other units alongside them. In despite of their overall limitations, the cheapest character to get onto the field and can easily be boosted to maximum. Several healers can be brought to the field with as much Psi as it takes to summon and boost 1 Dragon to its maximum boost level.