"That is the source material." -- Sort of. In reality, both the manga and the anime were released pretty much simultaneously, the one supporting the other. I remember, as I was involved in scanlating those first four chapters for Vortex. We did the first three chapters in quick succession in 2013, then Eien Scans picked it up and did the next two chapters. I didn't know about that. All I knew was we were sitting on chapter four for a long time when one of the Vortex guys decided we ought to complete the chapter. From my perspective, it was pure chance that our version of chapter four came out the day after the Eien version of chapter five... and which I never saw until today.
Working with magazine raws was a pain...