Zodiac

The zodiac is a concept in astrology, where a number of signs relating to constellations have influence on the world. The zodiac features predominantly in Homestuck, most notably through the trolls, but is also connected to the cherubs.

The twelve signs of the zodiac on Earth are the signs of the twelve trolls who created Universe B and due to their influence the signs appear to represent various traits of theirs. The trolls themselves are stated to have HS 4475 (48 signs), however their zodiac appears to be independent of the symbols assigned to the trolls, as they are based off HS 5374 (their class), with each class having a large alphabet of signs, and the Cancer sign is specifically derived from HS 5956 (a method of execution). Andrew Hussie has joked that the 48 signs of the trolls is because of the 48 squiddles that created their universe. In is worth noting however that Ptolemy in his categorisation of the constellations listed 48 constellations.

The signs

 * Aries (♈) - The sign of Aradia Megido and the Handmaid/Damara Megido.
 * Taurus (♉) - The sign of Tavros Nitram and the Summoner/ not Rufio Nitram
 * Gemini (♊) - The sign of Sollux Captor and the Ψiioniic/Mituna Captor.
 * Cancer (♋) - The sign of Karkat Vantas and the Sufferer.
 * Leo (♌) - The sign of Nepeta Leijon and the Disciple/Meulin Leijon.
 * Virgo (♍) - The sign of Kanaya Maryam and the Dolorosa/Porrim Maryam.
 * Libra (♎) - The sign of Terezi Pyrope and Redglare/Latula Pyrope.
 * Scorpio (♏) - The sign of Vriska Serket and Mindfang/Aranea Serket.
 * Sagittarius (♐) - The sign of Equius Zahhak and Darkleer/Horuss Zahhak.
 * Capricorn (♑) - The sign of Gamzee Makara and the Grand Highblood/Kurloz Makara.
 * Aquarius (♒) - The sign of Eridan Ampora and Dualscar/Cronus Ampora
 * Pisces (♓) - The sign of Feferi Peixes and the Condesce/Meenah Peixes.

13th and 14th signs
In 1970, Stephen Schmidt suggested the addition of two more signs, Ophiuchus and Cetus, while this suggestion didn't catch on, in 1995 a 13 sign system only adding Ophiuchus to the tradition twelve was suggested by Walter Berg and Mark Yazaki. The 13-sign system has gained traction and as such when the original twelve trolls were introduced many suspected a 13th troll to exist. Eventually a character that initially appeared to be a new troll appeared who used a Caduceus as their symbol. While not a constellation in itself, both it and Ophiuchus are connected to snakes. Later still, another characterwho used the exact symbol for Ophiuchus was introduced. The characters were later revealed to not have been trolls, but rather cherubs, a species having serpentine features, and also shared a singular body.