According to Kawahara Reki there supposed to be 10 [Unique Skills] on Sword Art Online. I know few of them.
- Dual Blades = Player with Fastest Reaction speed.
- Holy Sword = Strongest Player (GM giving himself the strongest player title)
- Darkness Sword = Highest Player Killing count.
All [Unique Skills] should be rewarded after Floor 90. What are other [Unique Skills] and requirement to unlock it ?