Bone Mail

Bone Mail, also called Bone Plate, is a recurring, and powerful, armor in the series. It often provides extremely high defenses, but at the price of making the user undead and vulnerable to Cure magic. It is also oftentimes found in the middle of the game.

Final Fantasy V
Bone Mail is the strongest armor in the game, defensively speaking. It provides a whopping 30 defense, +10 more than Vishnu Vest, as well as making the user immune to Instant Death, Poison, Blind, Old, Confusion, and Berserk and absorbing Poison elemental attacks and halving Ice elemental attacks. However, the downside to equipping the armor is that the user is also immune to Regen as well as being weak to Fire and Holy elemental attacks, giving -5 Stamina, and once the user is KO'ed in battle, they cannot be revived during the fight. It is advised to use with caution. One is found in Drakenvale, while others are won from Hades or stolen as rare steals from Necromancers.

Final Fantasy XII
Bone Mail is a mid-ranked armor that provides 34 Defense and +6 Strength, as well as halving Dark elemental damage, but makes the user weak to Holy elemental attacks. It requires 40 LP and the Heavy Armor 5 license to use, and costs 5900 Gil to buy.

Final Fantasy Tactics Advance
Bone Plate is a high-ranking clothing that provides 42 Defense and 8 Magic Defense, as well as allowing the user to absorb Dark elemental attacks.

Final Fantasy Tactics A2: Grimoire of the Rift
Bone Plate is a high-ranking light armor that provides 37 Defense and 9 Resistance in addition to absorbing Dark elemental attacks. It teaches the ability Strike Back to Parivir, Gladiator and Ravager for 250 AP.