We know Karkat’s bloodline is extremely cullabl cause he’s a mutant + a lime blood, but what do you think would happen if a troll of a higher blood was mutated, or even a fuschia?
Likely either mutations have nothing to do with the original caste color and it just can be anything, or each caste has a different ‘mutated’ color and there’s a whole Shadow Hemospectrum hiding from us.