Rune equipment

Rune Equipment (ルーン) is a recurring type of equipment in the series. In most games that it appears in, it is usually one of the stronger types of equipment, though some Rune equipment can be found mid-game. Rune equipment is related to magic, often either deals with using MP for automatic Critical Hits or dealing extra damage to Mage-type enemies. The most common recurring type of Rune equipment are the Rune Blade, Rune Axe, and Rune Staff.

Final Fantasy
The Rune Blade was originally the only Rune equipment in the game, doing extra damage to Mage-type enemies (bugged, not to work in the NES). From the Dawn of Souls remake onward, the Rune Staff and Rune Axe appear as well. The Rune Staff is a decent weapon that is most noteworthy for being able to cast Healara when used as an item.

The Rune Axe (usable by Warriors, Knights and Ninjas) is not only capable of casting Curaga when used as an item, but is also guaranteed to cause critical hits when its wielder has enough MP, making it a pretty powerful weapon. Every time you use the Fight command with a Rune Axe equipped, 25 MP is used up and all of the hits delivered are guaranteed to be critical hits. If the user has less than 25 MP however, the Rune Axe does not appear to be capable of dealing any critical hits whatsoever. To get the most out of this weapon, you will need to make sure the character wielding it has at least 25 MP at all times.

Interestingly enough, the Rune Axe is actually the strongest weapon to use in the game during fights where you plan on buffing a single attacker. With sufficient attack boosting via use of spells like Haste, Saber and Temper (or using Strength Tonics), the damage algorithms in both Dawn of Souls and the 20th Anniversary Edition cause the Rune Axe to do more damage than using even the Ragnarok or Ultima Weapon at maxed out HP would (due to its guaranteed criticals).

Final Fantasy II
The unique piece of Rune equipment in Final Fantasy II is the Rune Axe deals extra damage against Mages and also casts Fog when used as an item, and is also the strongest axe in the game if you exclude Guy's ultimate weapon, the Gigantaxe.

Final Fantasy III
The Rune Staff is a high level staff that can cast Erase. The Rune Bow is a mid-level bow while the Rune Axe is a mid-level axe that both provides +2 Intelligence and Mind. The Rune Bell is the second strongest Bell in the game. The Rune Bracers are the first armor type of the Rune Equipment, and is a mid-level armor that provides some resistance to status attacks.

Final Fantasy IV
The Rune Axe is the second strongest axe in the game, and deals critical damage against mages. The Rune Staff also deals critical damage against mages, and can also cast Silence when used as an item. Rune Armlet provides resistance to Silence, and increases Intelligence and Spirit by 3, as well as being a mid-level armor. It is Rydia's starting armwear when she returns to the party and can be bought from the Dwarven Castle.

Final Fantasy IV: The After Years
The Rune Axe, Rune Staff, and Rune Armlet return from Final Fantasy IV with the same stats.

Final Fantasy V
The Rune Axe is an axe which inflicts critical damage with 10 more Attack Power in exchange for 5 MP, and is one of the Sealed Weapons. The Rune Chime, known simply as Rune in the RPGe translation, is a Bell which also consumes 5 MP for a critical hit with 10 more Attack Power, and is the second strongest weapon of its type in the game. The Rune Chime also has the uncanny ability to increase the damage of all elemental attacks except Water by 50%. The Rune Edge is a mid-level sword that consumes 10 MP for a critical hit with 20 more Attack Power, though it is not found till late in the game.

Final Fantasy VI
The Rune Blade consumes 10 MP each attack for a critical hit, and can only be used by Terra, Edgar, and Celes.

Final Fantasy VII
The Rune Blade and Rune Armlet represent Rune Equipment in this game. Both pieces of Rune equipment have four non-linked slots and Double Materia growth abilities.

Crisis Core -Final Fantasy VII-
Rune Armlet is an accessory that boost Max MP by 80% and prevents Silence.

Final Fantasy VIII
Though it cannot be equipped, the Rune Armlet appears in the game as an item that can teach the ability "Spr +20%" to any GF.

Final Fantasy IX
The Rune Tooth is a mid-level weapon for Zidane that teaches him the ability "Lucky Seven", and has innate Poison. The Rune Blade is a high-level sword that only Steiner can equip that teaches him the ability Iai Strike, and has innate Darkness. The Rune Claws are Amarant's strongest weapons that teaches him Spare Change, Demi Shock, and Revive, and also have innate Darkness.

Final Fantasy X
Several weapons can get the "Rune" moniker by having the ability "Magic +5%" as the dominant ability. Tidus can also get the weapon Runemaster by having all 4 "Magic +%" abilities on a weapon.

Final Fantasy X-2
The Rune Bracer is an accessory that double the wearer's max MP.

Final Fantasy XI
Final Fantasy XI has a set of high-level Rune Weapons. These weapons each have different effects which activate when the weapon is drawn and consume MP over time. In addition to the special effects the Rune Weapons can mostly be equipped by Black Mages and Summoners regardless of the weapon class.

Final Fantasy XII
The Runeblade represents the Rune equipment.

Final Fantasy XII: Revenant Wings
The Runeblade appears again as a mid-level weapon for Vaan. The Rune Bracelet is an accessory for Penelo that increases the effectiveness of Dance abilities.

Final Fantasy XIII
Rune Bracelet is the only occurrence of Rune Equipment in the game. It grants +10 to 20% resistance to Magic, depending on its level, and can be upgraded to the Witch's Bracelet by using the Uraninite item. The Rune Bracelet can also be bought from B & W Outfitters in the Retail Network for 4,500 Gil.

Final Fantasy XIII-2
The Rune Tooth reappears as a weapon for Noel Kreiss.

Final Fantasy Tactics
The Runeblade is a high-level sword, and is the only Rune Equipment in the game.

Final Fantasy Crystal Chronicles
The Rune Hammer is a mid-level weapon with an Attack power of 25 possessing the Focus attack Shock Bomb. The Rune Shield is a high-rank shield that provides +18 Defense and Spell Range +20. Both the Rune Bell and Rune Staff are Magic-raising artifacts, raising Magic by 3 and 1 respectively.

Final Fantasy Crystal Chronicles: Ring of Fates
The Rune Saber, Rune Rod, and Rune Spoon all represent Rune Equipment.

Final Fantasy Crystal Chronicles: Echoes of Time
Rune Ax, Rune Bell, and Rune Spear, make up the Rune Equipment in this game.

Final Fantasy Legend III
The Rune Axe is the second strongest axe in the game, having an attack power of 100 and bought for 13000 G at Knaya in Pureland, or on board the Talon in Masa's shop.

Dissidia 012 Final Fantasy
Several pieces of Rune equipment appear in this game, consisting of the Rune Blade, Rune Axe, Rune Staff, Rune Bell, and Rune Armlet. All but the Rune Blade are level 30 equipment, with the Rune Blade being a level 60 weapon, and all apply different effects from one another.