Unarmed uses its own formula to calculate damage, which is the same as the Strength formula but it does not gain a +1 bonus, making it slightly weaker. Unarmed's Attack Power is also smaller than the weapons' using that formula, making it an undesirable option at face value. Damage is heavily reduced if a shield is a equipped.
However, the Attack Power of Unarmed becomes variable if the Brawler ability is equipped. Brawler is granted by the Brawler license and the Amber Armlet accessory. With Brawler equipped, Unarmed's Attack Power becomes , making it instantly more powerful because every character's base Strength is greater than the initial value.
In the Zodiac releases, since Unarmed is not bound to a license, anyone can fight this way. The job most suited to this weapon is Monk due to having Brawler on its License Board near to its Command license. The Shikari also has it on a far corner of the board, and Bushi has it behind the Chaos license.
Fighting oneself unarmed is a known trick in the RNG method that lets the player control the items obtained from randomly spawning treasures.