Spirit Killer is also known as Fairy & Fairies Killer that increases physical and magic damage against spirit monsters. The spirit killer passive abilities can be found in various types of equipment, materia abilities, and unit buffs.
As with all killer passives, players can gain extra damage boosts when the units have been maxed out.
Sometimes it may be beneficial to swap in a spirit killer item in place of a raw damage item that may provide little to no additional damage.
To find the killer gear for the spirit race click here to open the Killer Gear Finder