KOS-MOS is from the Xenosaga series and is (at least according to stingers) the best character ever made. Ever. If you don't like her, then I think you should consider suicide, for it truly is your only option.
For being a character from a relatively cult RPG series, KM has actually had some surprising success in the Contests. She has smashed Crash Bandicoot and Amy Rose, advanced ahead of Diablo and Arthas Menethil in 2007, and held up well in direct matchups with Ryu and Aeris. KOS has been a consistent mid-carder with the ability to finish in the mid 30s in the x-stats every season, aside from her one bad result (a 66% pounding at the hands of Luigi in 2005).