Hemospectrum pt.1
Okay, okay, I pulled myself together to be able to get this ramble down. To keep myself from derailing COMPLETELY, I'll try to stick to talking about the biological parts of the hemospectrum and avoid the social details. I know they're pretty strongly tied together so I'll fail badly, but I'll try to limit myself and talk more about bloodcastes at a later date. I also wanna warn you that this ramble's gonna contradict canon more than most of my headcanons. Please excuse that. I like overcomplicating things...
Anyways! *rubs hands* We all know what the hemospectrum looks like, right? Red, warm blood at the bottom, pink, cold blood at the very top- no wait. Not if you ask me.
Basically, in my (canon-contradicting, sorry 'bout that, I'm gonna stop apologizing because I'm having fun and have no reason to be ashamed) headcanon, the hemospectrum, rather than being a spectrum, is a circle of a sort. Like a color wheel. This color wheel then has two polarities - with rustbloods being the warmest color, highest chance of psionics, with the shortest trolls (on average) - and ceruleans being the coldest color with the lowest chance of psionics but the highest physical strength, as well as (on average) the tallest trolls.
With it being a circle of a sort, the colors blend into one another. So the 12 colors we see aren't the only ones - there's every shade in between. Though the blood colors of the "true sign" bloodlines are pretty close to the default, so, somewhat based on them, the rest of the troll population are sorted into castes. (If you're somewhere between teal and jade but closer to Kanaya's color, you're gonna be counted as a jade. If you're squished precisely between, you're a cusp and in a really fishy social situation.)
Blood colors are inherited from ancestor to descendant and they're *static*. Okay fine, they can change by like 0.5 of a value but that's *it*. However, (okay I gotta talk about this soonish too) if you're the kit of two fertile trolls, you're gonna have your blood color be somewhere in between your parents.
Anyways, the Condesce (oh god the Condesce, she has a role in half my societal headcanons) wanted to put herself on a piedestal so she made a spectrum of it with two very different polarities from the biological ones - where the rustbloods are filth and the fuchsias are royalty. Over the generations, through selective breeding, the old polarity has been more or less erased, so despite the warm blood of the fuchsias, they've made sure their every generation is taller and stronger than the previous.
This also means, because she wanted a spectrum rather than a circle, that everyone in between Fef-color and Ara-color are illegal now. Kill them all. They're not exctinct exactly but they're very very rare and considered *weird as fuck* because nobody can actually tell if they're higher than a fuchsiablood or lower than a rustblood.
Annnnd this leads us into mutants! There's four sorts of hemomutants, basically - off-spectrum trolls (being the ones mentioned above), limebloods, redbloods and miscellaneous.
Limebloods are, well, technically not mutants but they still have... basically the same level of rights. Dirty, gross bastards that you don't want in your gene pool. The Condesce made an effort to wipe them out until she realized you could sedate unruly trolls with their blood. So nobody sees 'em any more. Well that's because they're busy being strung up and used as sopor factories.
Redbloods are- okay I gotta give you some background information to tell you what redbloods are. Basically, trolls have a sort of pigment in their blood that gives them their various interesting colors (this pigment gets errywhere - hence their blood-colored eyes, tears, et cetera) that humans lack. Well, redbloods (then we're talking candy red, like Karkat) lack this pigment, which, in a way, also puts them outside the hemospectrum which is also dirty and we don't want.
Lastly, miscellaneous hemomutants are an unfortunate bunch - these are trolls with natural variations to their blood color that are *just a bit too strong* to be okay. Say you're a jadeblood but your blood color is really, really pale, or way too bright, or way too dark. That's not something they want you to spread! That's weird and there's probably something wrong with you. Cullbait. (These are really tricky because given that blood colors are inherited, you'd have to wipe out an entire bloodline...)
That being said, miscellaneous hemomutants can be excused if they're, otherwise, of a higher caste. Equius is very much on the border of having too bright blood, but he's left alone because he's a highblood. And nobody touches a fuchsia. That's like rule number one.
Speaking of fuchsias! I'm almost done but I sort of want to point out that I headcanon that fuchsias are... well they're rare, but they're not "only two fuchsias alive at any point in time". That's tyrians. Tyrians are a separate caste. Or, well, really, they're just one bloodline - the Peixes. They're the royal family basically, while fuchsias are a very aristocratic caste.
















