Deals lethal damage to demons.Description
Devil Killer is a support ability in Final Fantasy IX for physical attackers, allowing them to increase the power of their Attack toward demon enemies. It costs 2 Magic Stones to equip.
Killer abilities in Final Fantasy IX are reminiscent of weapons in the Nintendo-era Final Fantasy games that dealt more damage to specific types of enemies.
Obtained
Devil Killer is learned from Cross Helm, Thunder Gloves, Chain Plate, and Demon's Vest for variable amounts of AP; Amarant learns it the fastest at 10 AP, where Steiner and Freya require the most at 30 AP. Equipping multiple equipment pieces that all teach Devil Killer masters the ability faster.
Thunder Gloves for Freya and Steiner can be first found in Cleyra. They are not in a treasure chest, but a ! appears on the field in the area with the water wheel 
, near to the hanging sign. The player can also get a free Cross Helm for Steiner and Freya by unequipping it from Beatrix during the Battle of Alexandria.
Chain Plate for Zidane and Amarant can be first stolen from Beatrix in Burmecia, and is later available in shops. A free one is also found in Gargan Roo. Demon's Vest for Zidane and Amarant is first stolen from Meltigemini and is later bought in shops and found in Terra.
Mechanics
With Devil Killer active, using Attack deals 150% normal damage to demon enemies. It does not stack with other Killer abilities if the enemy belongs to more than one category, but does stack with MP Attack and Elem-Atk gear, and the attack can still critical. If the attacker also has Healer (only possible with Amarant), the amount healed with Attack is increased against demon enemies. Devil Killer affects any use of Attack command against demons: via Attack, Charge!, or Counter. It does not affect damage from any other move besides the basic Attack command.
Use
Devil enemies are fairly common later on, many of them found in Desert Palace, Ipsen's Castle, Terra, and the final dungeon. The ability is available to learn earlier than it is useful to equip. There are some demon bosses: most Chaos guardians, Tantarian, Meltigemini, and the superboss Hades. Though Tantarian is the first demon enemy the player may come across, physical attacks are not always a great idea to use against it, as it will close if hit with a physical attack in its open phase. Though there are some demons in Desert Palace, the best strategy in this area is to simply use Quina's LV5 Death in every random encounter. In Ipsen's Castle, the player needs to equip low Attack Power weapons for their Attack command to be useful.
- Devil enemies
- Devil bosses