User blog comment:ChishioKunrin/RWBY Volume 3 Livestream/@comment-94.67.176.119-20160211184535

Actually, it has been said through various livestreams that manga is canon and as well as the japanese localization, the authors worked closely with RT stuff (fun "lost in translation" story about Vol.1 Japan also...) while Grimm Eclipse is NOT canon but will have several referance to the actual show.