Board Thread:Speculation House/@comment-14640999-20140724024429/@comment-11188061-20140808060543

Not many people will be able to fight Penny. One on one, Team RWBY everyone will be obliterated by sheer firepower. With Team JNPR, Pyrrha has a distinct advantage against Penny, but Penny is like magnet resistant. Otherwise she'll mulfunction every time she gets close to something magnetic, and that doesn't exactly make sense. Jaune might be able to produce a barrier in the future that can withstand a laser shot, but nobody knows.

Mercury will lose, because he enjoys a good fight. Emerald has a chance where she can trick Penny and gut her from the back, but it hinges entirely on whether she can ensure that it is a one shot kill.

All of the sensei class (Roman, Ozpin, Glynda, Cinder etc) can beat Penny. If the first of sentient androids can somehow beat the entire galaxy of strong Hunters then Ironwood would have ruled Remnant long ago.