The Cleric is an all female character class, capable of using Staves (the male variant being a Priest). While low in defense and having no means of attack, the Cleric is a critical class to have on the battlefield. In the Fire Emblem series, a character who's HP is depleted to zero, is (in most cases) killed and unusable for the rest of the game. Having a unit such as a Cleric defeats the fear of permanent death with the ability to heal wounded allies.
Though entirely unarmed, the Cleric is one of the most important classes to have. They can heal allies for great amounts of HP, allowing the player to use them without the threat of possible death, and save healing items in case of emergency. As they are mostly portrayed in games, the healer is often defenseless, in the sense that they have little to no means of attack and low defense. It is highly recommended that Clerics are to be guarded and blocked at all times, not even giving the enemy a chance to strike. While a unit acts as defender, Clerics will be able to equally support wit healing magic.
The Cleric promotion is among one of the more useful upgrades. Clerics promote in a Valkyrie and are able to use Light Magic along with Staves, while mounted on a Horse for better movement. Having access to Light Magic means taking away the defenseless flaw and giving a means to attack, although their Light Magic is mostly considered inferior towards the classes who are already proficient with the same type of magic.