My guess is the original 'story' happened before Arcane regressed, the Dana from that time is the original Dana.
So after Arcane regressed, original Dana was already replaced by an irregular (reincarnator).
From what i understand, the current timeline (where the reincarnator resides) isn't the timeline where Arcane came from (Dana, servant ded, Arcane × Stella, Edgard blah vlah blah)
1st timeline = originally the plot of the 'novel' where no irregularities take place and the story progresses smoothly.
2nd timelime (Arcane's regression) =
Reincarnated person in Dana's body, Negative emotions between Arcane & Stella.
Unless the reincarnated Dana is like Raeliamna all over again, this would be my headcanon for a while.
That Kellen or Kellan is beautiful
Please behave for now