Per wiki policy, Spoilers Off applies here and all spoilers are unmarked. You Have Been Warned.
Violet is related to River Song.
Her full name is Violet Song jat Shariff. Enough said. Oh, and both ladies have a penchant for shooting things. The reason Daxus was able to hide the fact that he's a hemophage is because he drinks so much coffee.
Think about it - what does he do in the movie that none of the other hemophage characters do? He drinks coffee. Gives new meaning to the trope Must Have Caffeine. The ending is really Violet's Dying Dream.
Which is one reason why the computer can't count the number of weapons she has in her arsenal - her mind can't calulate that much and so settles for "many".