I really like what we've done here with Alexi versus Xi Shi. They seem like a very interesting battle.
Alexi's blade is made to cut through swords and break them, where as Xi Shi weilds a Zhanmadao, which was made from cutting down horses. This would mean both sword is very tough, canceling out Alexi's initial sword breaking ability. More than that hers was made purposefully thick and heavy to cut through blades as well.
However, Alexi has a wrist mounted blade, making it versatile and very close combat, allowing her to close distance and make the unwieldy blade Xi Shi uses and thus leave her blade to be more of a burden.
To cancel this, however, Xi Shi is trained is Chinese techniques and was given training in basic kungfu, thus allowing her to stop Alexi from closing the distance with punches, kicks and other unique strikes.
That being said, Alexi does have a wrist mounted blade and punches and kicks would be very dangerous knowing she could be impaled by the blade.
To finish up, both have outside of school combat training that makes them powerful.
It seems to be the only grudge yet and so I eagerly await it to play out!