User blog comment:Morning Star TM/RWBY - Weiss freezes a Death Stalker/@comment-26198742-20200208212922/@comment-44501217-20200209082504

Also, in a thread in Reddit, they stated that Kerry stated that the Manga was cannon to the show:

https://www.reddit.com/r/RWBY/comments/58lmhv/how_canon_is_the_rwby_manga/