Blood redirects here. For the aspect, see Blood (Aspect).
Featured Spirograph
Featured Spirograph

The hemospectrum is the series of twelve blood colors possessed by trolls, forming the basis of the Alternian caste system. Lusii share these blood colors, and often or always have the same blood color as their charge.

Cherubs also possess multiple blood colors, however in a binary rather than a spectrum, with only two colors.

Rust Bronze Gold Lime Olive Jade Teal Blue Indigo Purple Violet Fuchsia


Troll blood is colored by an ingredient similar to melanin specific to their position on the hemospectrum which saturates much of their bodies, including theirSburb Logo tearsSburb Logo. These colors are also found among lusii, who take care of trolls with the same blood color.

Lifespan and population

Trolls higher on the hemospectrum have longer lifespans, with rust bloods usually living only a dozen or two sweepsSburb Logo (26 to 50 years) and most lower blood castes living roughly as long as a human, with green castes having lifespans extending above a hundred years. Blue bloods live many sweepsSburb Logo longer than bronze bloods, and fuchsia bloods have an unparalleled lifespan of hundreds of thousands of years, or perhaps millions.

The relative population of each caste is inverse to their lifespan, with lower classes being much more copious than higher classes, and fuchsia bloods numbering only two. The exception to this are the jade bloods, which are said to probably have the smallest population of any individual class, aside from fuchsia in the commentary for Homestuck: Book 4. The relative population of males and females also differs from caste to caste, with blues, indigoes and purples being described asSburb Logo generally male-do+minated and jade bloods as an an almost exclusively female casteSburb Logo. Only female fuchsia bloods are known.

Psychic powers


Mindfang manipulating some impressiona8leSburb Logo lowbloods.

Trolls of lower blood are more prone to possessing psychic powers, with telekinesis common to both rust and gold bloods, and animal communion being typical of bronze bloodsSburb Logo. Trolls with psychic powers are more difficult to manipulate psychicallySburb Logo, but in exchange are more psychically susceptibleSburb Logo to Gl'bgolyb's Vast Glub and are the first to die when it occurs.

Some higher castes are also prone to specific psychic powers. Sometimes those of Aranea's 8lood typeSburb Logo are able to access another's mind to the extent of mind control and psychic manipulation. Purple bloods also have access to REAL HARSHWHIMSIESSburb Logo called chucklevoodoos which allow them to psychically amplify fears through dreams and manifest variousSburb Logo puppetsSburb Logo inside them.

Sea dwellers

Mutant colors

Though not true mutants due to their status as paradox clones, Karkat and Kankri Vantas' blood is referred to as mutant candy-redSburb Logo. Unlike all other trolls, their blood is the same color as humans' (as well as carapacians, leprechauns and malevolent cherubs).

Due to the rarity of this color, Karkat's ancestor was unable to receive a signSburb Logo and unlikely to be selected by any lususSburb Logo, and was raised by another troll, the Dolorosa, instead. His lack of proper place in Alternian society made him a pariah, forcing him to wander the world alone for many sweeps, concealing the color of his blood to avoid certain execution.

Doc Scratch suggests that this mutation was also the source of visions the Signless experienced throughout his life.

Though this color has no true place on the hemospectrum, the sign given to Karkat after his ancestor's death sits between Gemini and Leo just as lime blood sits between gold and olive. This duality of lime and red is reflected in the cherubs. The Extended Zodiac states that Cancer, for mysterious reasons, transcends the Sign Class Spectrum altogether.

Caste system

The caste system on Alternia follows a strict heirarchy up the hemospectrum in order of hue, with rust the lowest, bronze above rust, upward to fuchsia, the highest.

The term 'lowblood' is used to refer to the castes on the lower end of the spectrum, such as rustSburb Logo, but also to refer toSburb Logo blue bloods by trolls of a higher caste. Similarly the word 'peasant' is frequentlySburb Logo usedSburb Logo toSburb Logo refer to trolls of lower castes, but 'peasantblood' is used by Gamzee to refer toSburb Logo Equius.

The term 'highblood' is usedSburb Logo mostlySburb Logo toSburb Logo refer to members of the purple caste, and used as a properSburb Logo nounSburb Logo refers to the leaders of the land dwelling castes, described as a a self-governing bodySburb Logo kept in check by the sea dwellers led by Her Imperious Condescension. The carrier of the Grand Highblood title presumably holds a high position among the Highbloods. These Highbloods would seem to be synonymous with with subjugglators, who use their psychic chucklevoodoos to quell rebellion among their governed.

The sea dwelling castes make up Alternia's royaltySburb Logo and are a caste which rules over the entire species. Despite this and their position above the land dwelling highbloods on the hemospectrum, sea dwellers and land dwelling highbloods have a rivalry codified in traditionSburb Logo and are obligated to be at odds.

The two fuchsia bloods form the highest caste. Her Imperious Condescension holds the highest position in the empire, able to use her lusus' powers to threaten the castes below into submissionSburb Logo. Her descendants are heiresses to her throne, and are expected to challenge her for it upon reaching maturitySburb Logo.

Signs and hemotyping

Signs are assigned to trolls based on their caste, each of which has a huge alpha8etSburb Logo of them. The Extended Zodiac represents the canonical extended set of troll symbols, showing 24 signs for each caste. All trolls wear their sign somewhere on their clothing in the same color as their blood, with many trolls such as Eridan and Nepeta choosing to wear additional accessories in their blood color.

In addition to wearing their blood color on their clothing, most trolls practice hemotyping in addition to their typing quirk, which is the old tradition whereby one types in his or her own blood coloUr.Sburb Logo.

Some trolls are liable to avoid wearing and typing in their own blood colors in special circumstances. Karkat, for example, wears gray in order to keep his true blood color hidden.

Cherub blood

Main article: Cherub

Cherubs have two different blood colors: rather than forming a hierarchic caste system, they act as representations of a moral alignment, predisposed to either creation or destruction. Biologically they serve a similar purpose to reproductive sexes, with green blooded cherubs only able to reproduce with red blooded cherubs.


  • Most of the blood colors on the hemospectrum are distributed at roughly 30° angles on the HSV color system, deviating by only a few degrees. Lime and olive blood have the largest deviation, sitting at 73° and 82° rather than 90° and 120°, respectively. Olive sits between gold and jade rather than lime and jade due to being introduced later than the other 11 castes; however these hue deviations also help the two colors appear more visually distinct (as green has the largest hue range on the color wheel out of all primary and secondary colors).
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