|Source: SAO 52pk|
In SAO, Kirito is the sole possessor of the unique skill “Dual Blades”. This skill is said to be awarded to the player with the fastest reaction time. Kirito kept his unique skill a secret from the other player because he didn’t know the conditions of unlocking the skill. The chosen player is supposed to be the one who will stand against the final boss on the 100th floor, regardless of the outcome of the said battle.