Thanks for the amazing translation! Just to clear up some small details, it's not that Leo 'can't win unless he draws his sword', but that he 'can't compete with her with the sword'. And Lenny's not angry that Leo used Anne's technique, but because he forced herself to use Anne's techniques that she hates so much.
Thought I'd point them out, because it's a very important plot point that Leo's sword techniques aren't top-class whereas his wave abilities are monstrous, and to a lesser extent Lenny's love-hate feelings toward Anne.