Hemospectrum

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

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

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Biology

Troll blood is colored by an ingredient similar to melanin specific to their position on the hemospectrum which saturates much of their bodies, including their tears. These colors are also found among lusii, who take care of trolls with the same blood color. It has been implied both in Homestuck itself and Hiveswap Friendship Simulator that trolls higher on the hemospectrum have cooler body temperatures, while lowbloods have warmer ones.

Lifespan and population

Trolls higher on the hemospectrum have longer lifespans, with rust bloods usually living only “a dozen or two sweeps” (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 sweeps” 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 as “generally male-do+minated” and jade bloods as an “an almost exclusively female caste”. Only female fuchsia bloods are known.

Psychic powers

Mindfang manipulating some “impressiona8le” 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 bloods. Trolls with psychic powers are more difficult to manipulate psychically, but in exchange are more psychically susceptible 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 type” are able to “access another's mind” to the extent of mind control and psychic manipulation. Purple bloods also have access to “REAL HARSHWHIMSIES” called “chucklevoodoos” which allow them to psychically amplify fears through dreams and manifest various puppets inside them.

Sea dwellers

Trolls of the highest two castes are sea dwellers, “a sub-race of troll distinct from the commoners by mutation and habitat”, recognizable by the fins on the sides of their faces. Sea dwellers also have at least partially different internal anatomy to land dwellers, including a “Collapsing And Expanding Bladder Based Aquatic Vascular System”.

Mutant colors

Though not true mutants due to their status as paradox clones, Karkat and Kankri Vantas' blood is referred to as “mutant candy-red”. 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 sign and unlikely to be selected by any lusus, 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 hierarchy 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 rust, but also to refer to blue bloods by trolls of a higher caste. Similarly the word 'peasant' is frequently used to refer to trolls of lower castes, but 'peasantblood' is used by Gamzee to refer to Equius.

The term 'highblood' is used mostly to refer to members of the purple caste, and used as a proper noun refers to the leaders of the land dwelling castes, described as a “a self-governing body” 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 “royalty” 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 tradition” 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 submission. Her descendants are heiresses to her throne, and are expected to challenge her for it upon reaching maturity.

Signs and hemotyping

Signs are assigned to trolls based on their caste, each of which has a “huge alpha8et” 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.”.

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

Lime	Cherub mother / "Calamity" Calliope
Candy red	Cherub father Caliborn

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.

Trivia

• 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).