Version 3 had some foreshadowing regarding different paths to cataclysm - Cass or Elin - as visions from the Red King and Mirta. It seems that the catalyst which transforms Elin into a magical nuke stems from you putting a child in her, hence the cat/Ludwig chastising you.
Elin is a rather unique case when considering the constant reference to reflections, and this update spells it out quite plainly that one of you weren't meant to exist. If you took the whiteblood in version 8 the first part of the vision shows an exchange between two women - one of them pregnant - and the Moon Lady (Goddess of Reflections? Death?). That vision is presumably about the Queen being pregnant with the MC specifically, but more specifically that she accepted some kind offer from the mirror which led to twins rather than the MC alone.
To be fair, Catalina probably only saw an opportunity to avoid bloodshed by appealing to the faction that claims to care about people. The lords are the evil she knows, but the rebels were an evil she didn't know until your confrontation.
At first I also believed that the vision of the pregnant woman in front of the mirror was the queen. But now I have doubts. I found the theory interesting that it was the queen when she was expecting Elis, and the cause of Elin's reflection was the curse cast by the mirror. However, I think that perhaps this would not be the case. At first we must consider that the characters say that the white essence brings visions of the future. It is not mentioned by any character that the white essence brings visions of the past. Based on this premise, we must consider that it is a vision of the future. Although the hair of the woman in front of the mirror looks more like the queen's, the color of her skin and her thinner body are more reminiscent of Elin's body. And since the woman is pregnant, it would explain why her breasts are larger, if it is Elin. Regarding the setting, it is possible to verify that she is in an abandoned place, very far from the royal palace or some noble house, which perhaps also rules out the theory that it is the case of the pregnant queen expecting Elin, since we must assume that she spent the pregnancy period in the palace and not in an abandoned place. Apparently, it is possible that it is the queen or Elin in the future impregnated by the MC hidden in secret in some abandoned place.
Another interesting detail I would like to mention is that the vision of the pregnant woman in the mirror is followed by a scene of Elis appearing in a place with several other dead Elis. In the vision, the following message is mentioned: "For the new to arise, the old must die. Only then can the cycle continue", which raises the question that perhaps the "chosen one" is not Elis but his son, and for the son to be born, Elis needs to die, for the cycle to continue. In this case, the one who would interrupt the cycle would not be Elis, but his son.
I would also like to mention the first time that Elis uses the white essence with Lockart. In the vision, a woman is shown saying "I am carrying your child, Elis! And there is not much time left." Then it shows Elis dying. And then the woman is shown saying "Your legacy will live on in me... in our son." This suggests that the arrival of Elis' son could mean his death.
It is worth noting that the dev mentioned somewhere, which I don't remember, that the imperial chronicles from 1.0 onwards will be in another period in time chronologically - which would perhaps bring up the hypothesis of the chosen one being the child that will be born.
Anyway, the story is very well developed - I never thought I would see something like this in an erotic game. The dev has a lot of talent.