The Demon Mail is a mid-ranked heavy armor in Final Fantasy XII that boosts the wearer's Defense by 30 (Zodiac) or 29 (original), Strength by 5 and—unusually for a heavy armor—Vitality by 3. The latter makes it potentially good for any character wielding a weapon that takes Vitality into account for damage calculation: axes, hammers, and hand-bombs; in the Zodiac versions, these are the weapons for the Foebreaker. The Demon Mail is metallic for the purposes of the Magnetize debuff present in the boss battles against Vinuskar and Ultima.
It rarely drops from the Darkmare and Bull Croc, and is available through the Hunt Club sidequest on the Phon Coast by giving one Rare Game trophy to Blok, and then purchasing the Demon Mail from the Shifty-Eyed Merchant's store nearby for 4410 gil.
In the updated Zodiac versions, the Demon Mail is sold for 4,700 gil in Mt Bur-Omisace. It is found as a treasure in Barheim Passage's The Zeviah Span (90% chance to appear, 50% chance for gil, 50% chance the item treasure is the Demon Mail without the Diamond Armlet equipped), and Phon Coast's Cape Uahuk (70% chance to appear, 50% chance for gil, 50% chance the item treasure is the Demon Mail without the Diamond Armlet equipped), as well as in Trial Mode Stage 76 with the Diamond Armlet equipped. It still rarely drops from the Darkmare and Bull Croc.
Demon Mail is a mid level armor giving 30 or 29 Defense depending on version and 5 Strength and 3 Vitality. The strength bonuses make heavy armor ideal for frontline fighters, and the Demon Mail is a good helm to equip over any inferior equipment the player may have on anyone who attacks physically, although a gun-wielder does not benefit from the strength-boost. The Vitality boost makes it good for someone wielding an axe, hammer, or hand-bomb (Foebreaker's weapons in the Zodiac versions), though Strength affects damage dealt more, and so another armor that offers more Strength is still likely superior to the Demon Mail damage-wise. Vitality mainly affects the duration and resistance against statuses: ailments lapse faster with higher Vitality, and buffs persist for longer.
In the Zodiac versions, Uhlan, Knight, Time Battlemage, and Foebreaker can equip the Demon Mail, and so it is only useful to buy if the player has chosen these License Boards for the party. In The Zodiac Age versions, after fighting Belias the player can choose two License Boards per party member and so more characters can benefit from heavy armor, as it is usually a good idea to match jobs that use different types of armor to bolster light armor jobs' strength, and to give more durability to spellcasters.
One may want to skip Demon Mail in favor of the Bone Mail available concurrently (original) or nigh concurrently (Zodiac) from the shops.
demon is "an evil spirit or devil, especially one thought to possess a person or act as a tormentor in hell".A