I'm not sure. Maybe someone who read Phase Shift can fill us in. The way I understood it was like this: Ragna and Nu form the Black Beast and go back in time. This is the same timeline where Jin goes back to become Hakumen. That's what we thought as of CT, but in Phase Shift we learn that somehow Ragna separated from the Black Beast and got amnesia, along with having his right arm and eye disabled. Then while he's back there, he meets Celica and does the stuff we're seeing in the Six Heroes path, until he eventually causes the Black Beast to go dormant by combining with it again, after leaving things behind for Jubei. I'm not sure where CP Ragna comes into it yet. I just got up to the part where he's about to go back in time... so maybe he is Bloodedge after all.