[Clarste]

Originally Posted by Netto Azure

Spoiler for Answer:

It was based off reaction time of the player. Which she had more as she basically lived in the virtual world for a much longer time.

Spoiler:

No, it has nothing to do with length of time, or else everyone else from SAO would be Kirito-level. It's an innate talent of the players themselves. She also has lots of experience, but that has nothing to do with reaction time.