Dual Wield

Dual Wield, also known as Two-Swords or Double Sword, is a recurring ability in the Final Fantasy series. It is usually associated with the Ninja class. Like its name suggests, it allows characters to equip a weapon in each hand and thus attack two-times, using each of them once.

Final Fantasy II
All characters, including temporary-playable characters are capable of Dual Wield, as they can substitute Shields for weapons, and vice versa. This allows you to significantly boost your damage output since shields reduce your attack power.

Final Fantasy III
All characters are capable of accessing this ability, regardless of their job class.

Final Fantasy IV
Yang Fang Leiden and Edge can both equip weapons in each hand. However, unlike most other games, the weapons count as the same attack, and Yang and Edge cannot use them to attack twice.

Final Fantasy V
Dual Wield is the level five ability for the Ninja class. This was the first time in the series in which Dual Wield was an actual ability.

Final Fantasy VI
The Genji Glove Relic allows a character to equip a weapon in each hand. Due to a bug in the game, damage is reduced by 25% whenever a character equips a Genji Glove but only one weapon. The damage algorithm was supposed to give this reduction when two weapons are equipped.

Final Fantasy XI
Ninjas gain Dual Wield at level 10. It allows the Ninja to wield a one handed weapon in each hand. Ninjas can use a select few Great Katanas as well, but it is almost never done since they are so much more effective with two weapons. As Ninjas advance in level, they gain greater and greater dual wield ability that will shave off progressively greater amounts off of the delay of their weapons.

For Ninjas, this means they can basically use single-handed Katanas, some western style swords, and daggers. A lot of players choose to use Ninja as a subjob. This is especially true of Thieves, Dancers, Blue Mages, Rangers, and Warriors.

Final Fantasy Tactics
The Ninja has Dual Wield or Two Swords as a support ability. A character can be very powerful if Two Swords is equiped as a Support Ability in the Knight Job Class, as Ninjas cannot equip the more powerful swords that Knights can, without another support ability.

Final Fantasy Tactics Advance
Ninjas are able to learn the ability Double Sword from the Nosada. It is effective, as it not only allows you to equip two weapons, but by doing that, you'll be able to learn two abilities at the time, or learn one ability at twice the speed. This applies to all jobs, as long as Double Sword is the set support ability and that the weapon equipped has a skill that can be learned. If the weapon is a two handed weapon, double sword is nulled, which means no dual wielding of bows, greatswords, or greatbows.

There is no need to classify other weapons (spears, maces,broadswords, rapiers. etc) as being available for Dual Wielding because only humans in this game can dual wield, and there are certain weapons only available for other races to equip.

Final Fantasy Tactics A2: Grimoire of the Rift
Ninjas can learn the Dual Wield ability from the Ragetsu-denbu. The effect is the same as the previous game. While Humes can equip books, and in the case of the Agent class, guns, neither can be dual wielded, the second due to the Agent being unable to change jobs. This is one of the few abilities that requires 990 AP to master, along with the Ultima abilities and the Red Mage's Doublecast.

Dissidia Final Fantasy
Onion Knight gains the Dual Wield ability upon switching to the Ninja job class during his EX Mode.