[Masamune·1600]

Ultima Weapon has strength equal to the wielder's HP divided by 10. Thus, it can potentially have an attack power of 99, which far exceeds any other weapon in purely statistical strength. Masamune, the original strongest weapon, still follows in second with an attack power of 56. However, like their counterparts in other games, a variety of weapons have additional positive attributes, like free spells or stat bonuses. Ragnarok has an attack power of 55, but I would take it over the Masamune on the basis of its additional attributes. Just as in FFVI, it adds 30 to one's Evasion, and adds bonuses of +7, +3, +7, and +7 to Strength, Agility, Intelligence, and Stamina, respectively. Ragnarok also allows one to repeatedly use Flare. Lightbringer (obviously Illumina from FFVI) has an attack power of 48, but has the incredible additional bonuses of +50 Evasion and +7 for Strength, Agility, Intelligence, and Stamina. Lightbringer also allows repeated use of Holy. Those are my four favorite weapons, although many people like to give Black Wizards the Judgment Staff, which has a +3 Intelligence bonus and repeated Flare use. Murasame, similar to its counterpart in FFIV, has +5 bonuses in Strength and Intelligence. However, it has -5 penalties in Agility and Stamina. Its attack power is 50, and related spell is Protect.

I noted these weapons, as I feel they are the strongest examples, if one's main interest is in dealing damage to the enemy. Ultima Weapon can be equipped on all upgraded classes, Masamune on all classes, Ragnarok on Knights, Lightbringer on Red Wizards, Judgement Staff on Black Wizards, and Murasame on Ninjas. Rune Staff, a White Wizard exclusive weapon, might be a nice choice if healing is a priority; it has a +10 Intelligence bonus and repeated Healara use.