Sheena Fujibayashi is the all-essential hot female ninja in Tales of Symphonia. But that's absolutely all she's good for. Being a sexy whore.
In a Contest setting, she doesn't appear to be good for much else either, if the 2006 Contest is any indication. Sheena was beaten soundly in R1 by Jill Valentine, who went on to get knocked off by Peach (though to be fair she at least lost in epic fasion). That left Sheena rated a little bit over the fodder line in the '06 x-stats, but how much that number can be trusted after Zelda overperformed on Samus is very much up to debate.
On an interesting note, Sheena is the 200th character to enter a Character Battle.