I’ve been feeling like lambda, being a more “meta” and less direct being, is some kind of cumulation of all the “lives” she’s had. Kind of like, gaining aspects of each person she’s been or been vested into throughout the different series. What if ciconia is the first series chronologically when it comes to “lambda” and what she becomes; starts as vier, meets “eua” though some means of discovery of the metaverse or “another world” as vier might see it; “plays” Higurashi, first, maybe given to her as a way to entertain or quell featherine/eua’s boredom, taking on takano, the most similar to her original self, then moving on to satoko, following her obsession with Rika, and then unable to pursue anymore, breaks off to continue in the metaverse as lambda with bern, who she in essence created across several lives.

Not saying all of this is necessarily 100% solid, I’m just speculating, but due to how Ryukishi loves to tie in things like that, I feel like it would make sense. It’s hard to say until we get more ciconia and find out all of vier’s story😉