User blog comment:B214/Volume 22 spoilers/@comment-30924344-20170128052407/@comment-9595671-20170128175738

@Bennia Lover: Actually Kiba's sword is an irregular Holy Demon sword, and Xenovia has had Durandal and Excalibur fused together as Ex-Durandal.

Ironically, it seems she's stronger when dual wielding so it's better for her to not fuse them, the primary example being it's the only time we've seen her use her Cross Crisis attack.