User blog comment:B214/Volume 21 info & spoilers/@comment-83.7.231.243-20160708091406/@comment-82.199.215.75-20160708153146

But B214 you didn't quote the next part of the chapter, where Loki says that it is too early for Xenovia to take on a god, implying that with sufficient training it might be possible.

My theory is that Caliburn and Gram have the power to take on a god, while Xenovia can match it with ExDurandal, but not with Durandal only.