Monsters are a type of enemy that only appear in Fire Emblem Gaiden, Fire Emblem: The Sacred Stones, and Fire Emblem: Awakening. They are apparently creatures created using Magic and usually serve powerful foes, such as the Demon King of legends in The Sacred Stones. They can appear as enemies in the main storyline, but are more often seen in repeatable optional maps. The Manaketes in The Sacred Stones are said to be halfway between man and monster. The weapons that monsters use vary between monster classes. Some monsters, such as the Bonewalker and Wight, use normal weapons such as swords and lances, while other mosters, such as the Revenant, use claws, allowing those weapons to have infinite uses. Monster-exclusive magic also has unlimited uses. If monster-exclusive spells are obtained, through glitches or hacking, they can be used by anyone because the weapons do not have any weapon rank assigned to them (the same thing happens with the spell Ereshkigal in Rekka no Ken ). For example, the monster weapon Stone is used to allow magical classes the use of dark magic, as it is the only monster weapon to give weapon experience for any weapon level.
Monsters are weak to Sacred weapons, and specific classes (Manaketes and Bishops in The Sacred Stones).
Monsters also show up in TearRing Saga: Utna Heroes Saga. All monsters from Gaiden make a reappearance, and some monsters exclusive to the game include Harpies, Ogres, and Golems. In that game, monsters can be created using certain staves by characters with the Summon Skill. This is the only time monsters show up as anything other an enemy.