The Secret of the Armored Warrior

I don't know since when, a kind of monster called a supernatural beast appeared. This kind of monster is brutal and murderous. It ranges from poultry and beasts to humans and companions. In order to stop them, a non-governmental organization called "FD" was born. They control a bell called "FD". The weapon technology of the "Armor Warrior" easily defeated the supernatural beast under the witness of people. Many people envied this power, but were afraid of it. Of course, it was more of an opportunity, because once you have this ability, you will face the fate of having to fight for your whole life.