Those who specialize in curing wounds. From the shadows, they have always supported the Huntmen. In addition to healing all of a party’s wounds, they are capable of defending themselves from the enemy.
Healers is one of 7th Dragons support class. They can heal and restore MANA and is the only class that can cure all status ailments and resurrect. Otherwise they can afflict poison and make is stronger and more durable. They can also be a good melee fighters but they are too low DEF, though. They have lots of useful skills like Enemy Sense (敵感知), Invisibly (インビジビリティ), Dead Man's React (デッドマンズリアクト), Great Worker (グレイトワーカー)and much more.
If you don't have a Samurai with Demonic Countance you might want Invisibly if you don't like random encounters. If you want a Attack Healer be sure to equip the strongest weapon you can get to the Healer and get the Healers DEF at high as possible. If they you SP left you can pick a level at Enemy Sense. These are common types of Healers:
Orthodox Healers are the healing Healers. If you have a Mage or other MANA intense class you can start with Recovery Mastery (回復マスタリー) level 5 → INT bonus level 5 → Mana Craft (クラフトマナ) level 5. Cure I level 5 → Recover I (リカヴァI) level 5 → Recover II (リカヴァII) level 5 → Resurrection (リザレクション) level 5 → EX skill Vessel of Miracle if you don't. The second alternative is more recommended. But if you have a Mage the Mage will easily run out of MANA. Recover I will recover status ailments from 1 to 4 in this order: Blind → Paralysis → Sleep → Poison. At level 5 it will decrease the MANA cost from 3 to 1. Recover II will recover status ailments from 1 to 4 in this order: Confusion → Curse → Fear → Petrify. Like Recover 1, at level 5 it will decrease the MANA cost from 3 to 1. When you're done with that start with the opposite build and start level Cure II (キュアII) to level 5. If you have 8 SP left you can just level Cure II from level 5 to level 10 for massive healing (the MANA cost will dramatically drop from 7 MANA at level 9 to 5 MANA at level 10).
Venom Healers are very MANA intense, so you might want another Healer with Mana Craft or a Princess with Song of the Moonlight. Max Venom Mastery (ベノムマスタリー) and Venom (ベノム) or Venom Mist (ベノムミスト). Pick up Cure at level 5 so he can do some healing. Take Venom If you want to save SP and can take out mobs without much trouble. If you have it hard to kill mobs use Venom Mist, though, Venom is more recommended. Venom Infecter (ベノムインフェクタ) works like a veil and counterattack with a small chance of poison if the casted get hit by a physical attack. If you want it you can cast it at a provoking Knight or just a ally that seems to be most likely to be hit. But that might not be necessary. When you have raised Venom/Venom Mist to level 7 raise only a level at Venom Amplif (ベノムアンプリフ). Venom Amplif is a skill that makes the poison stronger and more durable. Once the enemy is poisoned use Venom Amplief and continue to use it each turn (or as often as possible if you need to heal). After a few turns with Venom Amplief the Poison will be pretty powerful. After you're done with that go for the Orthodox build.
The Attack Healer is pretty hard to use. Late game, when they grab the ultimate weapon for Healers he will show his true potential. Though, that's a long way. First give him Cure I at level 5 so he can heal. Then raise POW bonus to level 5 and max their main attack Swing Crush (スイングクラッシュ). After that level up POW bonus to level 10 and pick up EX skill Earth Breaker (アースブレイカー), if you want (though it would be better to spend EX at Swing Crush). When you're done with that go for the Orthodox build. Unfortunately the Attack Healer will be outpaced compared to the Samurai, Rouge and Fighter. So if he wants to catch up he must use Swing Crush every turn. Remember that the Healer has low DEF so placing him at the front row will let him die easily. So it would be recommended to have a Knight that can protect the Healer and/or a Princess that can increance his DEF with Solid Rhyme.