User blog comment:(Spoiler Warning) Dniv/Mikoto is now a badass?/@comment-4882213-20131015010159/@comment-11571396-20131015030849

I don't get what you're confused about. Kihara Gensei attempted to shift Misaka into Level6 during the Daihaseisai. As there is no mention of it later in the novels, we can safely assume that the experiment failed and Misaka never reached Level6, instead reverting back to normal.

Seriously, that's what the wiki is for, how can you not find what you're looking for?