Think there might be some manner of bug related to "The Beast". I realized something was wrong when trying to go to my first Dual-Affinity Town, and the text randomly started talking about a "Beast" I had no clue about. At first, I had been disappointed and assumed it was AI hallucination, since I know the game uses it to a degree, but the dialogue had kept coherent up to that point.
However, talking with other players, I think I might have somehow missed or bugged through what the game assumed was a mandatory flag, as apparently I was supposed to find a Beast companion at some point before the Harmonized Town (and also apparently a ruined town? Never saw that either, just went straight from mono-elemental town to Harmonized), but for some reason just didn't.
Just thought I'd post a comment about it so the issue is known, and also to know if not having this Beast has basically softlocked my save.