All of my headcanons that I follow in six :3 (The first three revolve around the same thing so it was right to follow both). Before you read this you crazy people FEFERI WAS NOT SERESTS MOTHER OH MY GOG. THATS OVER THE LINE JUST NO. NOPE. JOHN IS NOPING RIGHT THERE. NEPETA IS NOPING. ALL THE SHIPPERS ARE NOPING.
1. At max three tyrian bloods are born in 10 sweeps. They choose the first born as the heiress and the others live in the same class as violet bloods.
2. Mutants can have very short lives such as only living up to 12 sweeps (thus the fate of Karkat if not for Feferis life extending powers) or living as long as tyrian bloods, which somehow in some weird culmation was the unfortunate fate of Serest.
3. When the genetic material is randomly mixed the material is literally randomly mixed. It is possible that the genetics of a low blood and a high blood can be put together and mutant blood (if they are not culled as wrigglers) and be mixed with the highest (though it is extreamly rare that they would be and almost) which was the peculiar fate of Serest.
4. Sea-dwellers don't mind eating other fish, for fish eat other fish.
5. There is such thing as other colors in the classes. There are the "pure" colors which are the mutant bloods. The royalties (such as violet and tyrian) are treated as the two highest class of land-dwelling trolls. The land dwelling royalties are treated as midbloods. The midbloods are treated as lowbloods and the lowbloods are culled at birth.
6. Once there was a higher class of tyrians. They where the maroon bloods. But like the limebloods they where wiped out because they had longlife and powers. Which through everything off the spectrum.
7. "Viridian" is also known as "lime blood". (Which brings in Winter who had survived because technically she was of great power and the cullingdrones thought it would be best not to mess with her, which is true for she did have powerful gifts)
8. Many sessions happened all over alternia, to "conserve" the population. So not everyone died, the players just do not know it.
9. Not just crab-lusii where made for mutant trolls several different kinds where created for them, such as wolves, birds and other creatures.
10. For the lack of classes for sessions, hundreds where made, The reason only 12 have been mentioned is because they where the only used in those sessions we know in the canon.
Please do not be mad! they are made because the story would not make sense.