C154 Flag for Summoning Souls(1)
Mo Xue wouldn't specially kill people for it to collect soul fragments. However, if she killed someone in the future, she could store it in the soul flag. Moreover, Mo Xue often went to hunt demon beasts, so they were all allowed to dissipate. If she could trap all of them in this soul flag, then she would have an army of demon souls in the future.
It was a pretty good item