So as we’ve discussed, it seems pretty likely like witches represent ideas. This would explain why they’re considered more powerful than humans and use them as ‘pieces’—because they represent abstract forces.
First, there’s Beatrice.
Beatrice originally represented Sayo’s imagined magical alter ego, but she grew to personify ‘endlessness.’ However, she doesn’t represent endlessness in a general sense; only for the ‘catbox’ of October 4~5, 1986. It’s possible that she could have grown/could grow to represent it in a general sense. This would fit with what Lambda says in her memoirs about Beatrice possibly having greater potential than her or Bern.
Also, that’s the reason Beatrice continues to exist after Sayo dies—because the catbox is still intact.
(Higurashi spoilers) Bernkastel originally represented the “dark” side of Rika that developed from living the months and years before June 1983 over and over. After splitting from Rika in Saikoroshi-hen (when Rika sheds her ‘witch’ mindset), Bernkastel grows to also represent the concept of miracles.
Then there’s the matter of Bern being the name of Ikuko’s cat, but I don’t know…
We don’t really know who Lambda was before she became a witch, but like Bern, she lived through some kind of hell, and eventually grew to personify the concept of certainty.
Uh…I’m stumped by this one. Obviously she’s based on Kumasawa, but she doesn’t seem to be a witch in the usual sense. She doesn’t seem to represent anything, either…
Much as in Sayo’s case, Maria’s witch form is her imagined magical alter ego. She also loosely represents the concept of ‘creating something from nothing.’ As @WitchOfGames says, she could presumably grow represent that concept in general, thus becoming a very powerful witch.
Originally Eva’s alter ego, EVA-Beatrice later grew to probably personify the Eva culprit theories that sprang up after the Rokkenjima incident.
Well…she represents truth, obviously, but other than that I don’t know. Some people say she was a person who died at sea who was adopted by Bern as her piece, but it seems extremely unlikely that her name would just happen to be ‘Erika Furudo.’
Meta Battler represents Tohya before he lost his memories. Beatrice drags him into her game, and he eventually succeeds Beatrice in representing the endlessness of the Rokkenjima catbox.
Featherine is made up of the writing duo of Tohya and Ikuko, right? But isn’t Featherine supposed to be ancient? Or at least older than Lambda and Bern? Well, here’s my theory…Featherine has “died” multiple times, right? Well, maybe Tohya and Ikuko simply ‘resurrected’ her. So in a way, they created her, but in a way, they didn’t.
ANGE is, you guessed it, the magical alter ego Ange developed after reading Maria’s journal. Bern formally made her a witch when she jumped off that building, and she came to represent various things.
So my remaining questions are…
I guess the biggest one is the whole chicken-or-egg problem… Is the meta-world a reflection of the real world, or does the real world develop from the actions of those in the meta-world?
Also, what’s the difference between witches and other meta-beings? For example, Will and Dlanor represent things, but they aren’t witches.