#thank you for your inquiry! nobody else better insist to me that they're identical ever again after this

[rubensmuse]

i just read your tags on a post from a few days ago and?? do you think the tridentarii aren’t identical twins?

My instinctual answer to this question is "You think the Tridentarii aren't fraternal twins?" Because making the snap judgement that they must be identical is just not as intuitive as this ask is implying it is. They're two different builds and color palettes, and Coronabeth has a different hair texture, so it really surprises me that them being "identical twins" is the assumption to which everyone defaults.

The thing that muddies this discussion for me is that, when people on the internet ask whether or not the Tridentarii are "identical", I have no idea if they mean "they look the same!" or "I headcanon that they are the result of a single zygote splitting into two embryos and developed identical genes!" Because those are two different things, and they involve making two different arguments. I get the sense that when people assume the Tridentarii are "identical", they are saying 1) they are monozygotic twins, but also 2) they would have the same phenotype and be indistinguishable if Ianthe didn't have necromancy eating her titties and muscles or whatever. (Which is also a silly thing to assume, because necromancy doesn't eat your pigmentation, but whatever.) Admittedly, Macaroni and Cheese being different shades of blonde is what made me assume they were fraternal, and that isn't a safe assumption for me to have made because genetics just aren't that simple (see this example of monozygotic twins being born with two dramatically different levels of melanin). The other factor here is, y'know, Ianthe being a necromancer, something hazily theorized in-universe to be genetic (something which, to be fair, we don't know for sure, see this fan theory), and if that is true, boom, there you go, fraternal.

But the other thing we have to consider is that the Tridentarii aren't, like, real. We are talking about fictional characters, so where you or I come down re: their genetic similarities will only matter insofar as it changes the meaning of the narrative. If Ianthe and Coronabeth are "identical" in the genetic sense, what does that mean for their story? Does it make any difference? Is there a purpose to me writing this dumb multiparagraph essay in response to a two-line ask on tumblr, other than to be contrarian and jerk myself off??

I mean, I think so. I think Ianthe's and Coronabeth's story is defined by them not being like the other. They are the two faulty halves of a theoretical complete heir; the platonic ideal of the Princess of Ida, with charisma and likeability and necromancy, too. Their parents "wanted a matched set", but they didn't get one. Them trying to correct this discrepancy with lies and secrecy that isolates them from everyone but each other fits in perfectly with all the other frictions of being a fraternal twin. Like, what's the point of you both? Why'd your mother go through all that trouble to get a pair of shitty normal siblings? And it's easy to internalize that, too, that expectation of unity contrasted with that reality of duality. We are one unit, but you are not like me. If we got here at the same time, why can you do things I can't. Well, fine, then, you have your Thing, I'll have my Thing, too; we're better than a matched set, we complete each other. Hang on, why does your Thing let you do something I can't? Where are you going. Take me with you.

Ianthe and Coronabeth are a set trying to be a match, and they can't make it happen, and it drives them so crazy that Corona would rather be killed and eaten than have Ianthe go do something she can't participate in.

TL;DR: Ianthe and Coronabeth are not literally identical (they are not physically indistinguishable). We don't know if they're genetically identical (monozygotic twins as opposed to dizygotic), and the distinction has not become relevant in any of the books thus far. AND I think considering them to be genetically identical makes their story thematically weaker when compared to the alternative. Therefore, I consider them functionally fraternal until Tamsyn Muir herself says that they aren't, and I furthermore remain flabbergasted that anyone in the fandom would consider that a weird interpretation.