The Atlantica Monk is quite literally the most important part of any formation. The ability to use Holy Guard to remove and prevent debuffs and damage for some turns is vital, as is the ability to use Awakening to remove stuns from your own mercenaries. This is to say nothing about the huge defense boost and bit of healing that they award to your main mercenary with Protect at the beginning of every turn.
Healing which also stacks with a Prophet's or Princess' or Exorcist's healing, should you have any of those and be running a main of the respective class(Atlantica Online Gold). Shield of Protection, the other passive skill the Monk gains, is a little bit unusual. As of right now, it apparently is not working quite as intended as it drains a bit more mana than it should.
Even so, it's relatively useful in situations where your main may be getting hit often for low amounts of damage, such as a ranged mercenary that gets hit at the middle or back line by cannons or guns: the amount of healing it does tends to do quite often makes the amount of total damage you take from cannons or guns very, very small. Even with that, however, it's not a very popular choice among monks and could probably use some revising and re-tooling. Here is Atlantica Online Gold.











