Slayer (魔物特効 Mamono tokkō, lit. Demon Slayer) is a skill that appears in Fire Emblem: The Sacred Stones, although a predecessor to the skill appears in Fire Emblem Gaiden. In Gaiden, when a Falcon Knight attacks a monster unit, a small circle of angels will encircle their lances during the attack animation (similar to that of the Angel spell), and their base damage will be tripled.
In Sacred Stones, the Slayer skill is a class-specific skill, and is learned when a unit is promoted into a Bishop. This skill essentially makes all spells cast by Bishops effective against monster units.
As an example, consider the case of a Bishop casting a Shine spell, which has a might value of 6, against a Revenant. Normally, this attack might deal 22 points of damage. However, with the Slayer skill in effect, the spell's might is tripled to 18, dealing a total of 34 points of damage.
- When using the Sacred Twin tome Ivaldi with a Bishop, its ability to inflict twice the damage on a monster will override the Slayer ability, resulting in said Bishop's attack being lowered. This makes the A-ranked Light spell Aura more effective in that sense, with the Ivaldi tome being put to better use by either a Valkyrie or a Sage.
- A common misconception about the Slayer skill is that damage triples in might against monsters. It simply triples the might of the magic tome in question, acting as a class-buster against monster units.