I always thought that trolls had reaaallyy high blood pressure concrentrated in their veins, giving them black lips and grey skin (like how food dyes are really dark??) And the ability to bleed excessively and stay alive (*cough* gamzee *cough*)

I mean, grey skin and black lips could just be the way their bodies are naturally colored by bullshit pigmentation stuff which I know nothing about so don’t take my word for it ssssh.

But having the ‘Highblood’ and ‘Lowblood’ difference be literally because Lowbloods have Low Blood Pressure and the Highbloods have High Blood Pressure is interesting. Specially considering Lowbloods are culled by the dozens and Highbloods are more important, it’d be like, a Lowblood gets a limb cut off and it kinda dribbles out little by little, but you cut a Highblood’s arm off and it’s this obscene gush of blood and everyone’s screaming.

I like this Headcanon.