Lusus

The Lusus Naturae (Latin for "game of nature"), also known as custodians, are the Hivebent equivalent to a Guardian. They look after the young trolls whilst the adults besiege other star systems in the name of Alternian glory. Trolls and their custodians have a peculiar arrangement of codependence. The lusus behaves as a lifelong bodyguard, caretaker, and visceral sort of mentor, while the young troll must learn to function as a sort of zookeeper.

They are horrifying beasts found in the ceremonial brooding caverns once the young trolls have completed their many dangerous trials. Together the young troll and custodian surface from the subterranean vaults and build a new hive using carpenter drones.

It was revealed that all of the trolls' Lusii would die due to the effects of the Mobius Double Reacharound Virus, and that all but one would be used to prototype their respective troll's Kernelsprite. They were all protoyped before entering the medium so the Troll's enemies have all their characteristics. Through the prototyping the Custodians gained the ability to talk with their charges for the first time.

It seems likely that the custodians will each correspond to the zodiac symbols of the trolls. Each custodian will presumably share its troll's blood color, or have color similar to as seen here and there, as well as sharing the gender of their respective troll.

The plural of Lusus is Lusii.

Aradia's Lusus
Aradia's lusus is a sort of goat/lizardish thing with ram-like horns similar to her own. Since it died well before the game of Sgrub, its death as a result of a chain of events stemming from a roleplaying accident, Aradia's Lusus is the only one not prototyped into a kernelsprite.

Vriska initially used her mind control powers to throw Tavros off a cliff, crippling him. In response, Aradia summoned the spirits of all the trolls Vriska had killed and set them upon her. At the urging of, Vriska retaliated by using her mind control powers to take control of Sollux. Vriska forced Sollux to fly to Aradia's home and consume a jar of mind honey, which caused him to accidentally unleash a burst of psionic energy, destroying Aradia's house with her and her Lusus inside.

It is possible that Aradia's Lusus is now among the 'voices of the dead' talking to her. One implication of this, if confirmed, is that her lusus is also in control of her fetch modus.

Tavros's Lusus
Tavros's Lusus, strangely enough, is a fairy/bull hybrid lusus that's barely any bigger than his head. Its name is Tinkerbull. They seem to have a very good relationship, often playing Fiduspawn together, and accompanying him on his Flarp adventures.

It appears to have been killed by Tavros, who had inadvertently crushed him underneath his wheelchair in a particularly cruel twist of fate for poor Tavros. Later, Tinkerbull is prototyped into Tavros's kernelsprite, seen floating outside of his transported hive.

Tavros has stated that, since Tinkerbull can now talk as a result of his prototyping, he is "really smart" and appears to consult him for advice.

Sollux's Lusus
Sollux's Lusus is a large two-headed, horned giant called a Bicyclops. It has one eye on each head, one red and one blue, fitting with Sollux's red/blue theme, and a mouth below each eye with two fangs. It eats mind honey, harvested from Sollux's beehouse mainframes, to "keep it from being an idiot all the time".

Sollux chains him to the roof of his communal hive stem, (apparently the troll equivalent of an apartment building).

It has likely been killed by the catastrophic release of Sollux's psionic energy that demolished the upper levels of his hive, as a result of inadvertently consuming mind honey.

Karkat's Lusus
Karkat's custodian is a towering, bipedal crab monster with a taste for chilled roe cubes. It is very crabby and Karkat is forced to fight it often to calm it down.

It was killed when Karkat's computer exploded as a result of running Sollux Captor's Mobius Double Reacharound Virus, thereby implementing the curse that possibly lead to the death of the other troll's lusus as well.

Shortly after its death, Karkat prototyped his kernelsprite with his lusus.

Nepeta's Lusus
Nepeta's lusus, Pounce de Leon, is a small feline creature with two mouths, and is "pawssibly the cutest and purrhaps the bestest kitty you have ever s33n!". She and Nepeta often went on adventures together to search for the "fountain of cute". Nepeta would ride on Pounce's back until Pounce got tired, at which point Pounce would ride Nepeta.

Pounce de Leon was crushed when Nepeta's hive caved in for currently unknown reasons.

Kanaya's Lusus
Kanaya's Lusus is a Virgin Mother Grub that gave up its responsibility to produce eggs. It is an honor to have one become your Lusus.

It has a skull-like face, lips, and two horns, one of them bent like Kanaya's.

It is possibly based off of the Grammia virgo, or Virgin Tiger Moth.

Kanaya was chosen by her Lusus on account of her rare jade green blood, protecting her from the various threats of the desert that her hive occupies. Kanaya's hive was built underneath the sand, the seed planted through use of her Lusus's remarkable burrowing skills.

Kanaya's Lusus apparantly died of natural causes, as a Mother Grub who renounces brooding has a more limited lifespan. Kanaya believes its death, and by extension the deaths of the other Lusus, are not an effect of the Mobius Double Reacharound Virus, as Karkat and Sollux believe, but instead are a consequence of playing Sgrub. After it dies, Kanaya saws open the abdomen of her lusus, removing a mysterious sphere covered with what look like troll horns called a Matriorb, not to be used until she was "ready", whatever that may entail. Doing this is part of Kanaya fulfilling "her end of the bargain".

Terezi's Lusus
Terezi's lusus is a large sightless dragon. The species apparently is born without sight and must learn to function that way themselves.

She was not directly raised by her lusus as the hatching of its egg would tip the Doomsday Scale and cause the end of the world. Her Lusus would telepathically communicate to her during her sleep. After Terezi's accident it was her Lusus that helped teach her the skills to function without vision, by smelling and tasting her surroundings, much like the dragon. By doing so, Terezi was able to connect with her awakened Dream Self.

The heat of a meteor-sparked forest fire causes the dragon's egg to hatch while Terezi watches. It dies, struck by a meteor, presumably due to an inability to see them raining down at the time of its hatching. Her corpse was later picked up and deposited into Terezi's kernelsprite by Gamzee, allowing the two to have audible conversations.

Dragonsprite was later seen around Terezi's hive in the medium.

Vriska's Lusus
Vriska's lusus is what resembles a gargantuan spider. Its face bears a striking resemblence to someone else. One of its fangs is bent downwards, like one of Vriska's horns.

It is stated that her lusus eats trolls, and is constantly hungry. Vriska uses her Flarp sessions to procure more food for her lusus. The massive lusus dwells in the webs woven in the canyons surrounding Vriska's castle-like hive, precariously located underneath Vriska's chain-suspended doomsday device.

She appeared to have been killed after the Catenative Doomsday Dice Cascader malfunctioned and exploded. The blast blew up part of the rockface that supported part of Equius's hive, which caused the rock and collapsed section of the hive to crush her.

Later, Vriska finds her lusus bloodied and struggling to survive under the debris. She put her lusus out of her misery, by rolling her enchanted dice. It unleashes one of its many forms of attack and a massive guillotine beheads the lusus.

Equius's Lusus
Equius's lusus, Aurthour, looks like a centaur, but with an udder and a mustache. He resembles a creature from one of the author's older works, Humanimals. In addition to being a guardian, Aurthour is Equius's butler, providing him with his own Lusus Milk.

Equius cares for or respects Aurthour on a certain level, and refers to him as "simply the best [butler] there is."

Aurthour bruises incredibly easily for a lusus, even as a result of a gentle, grateful pat on the head. It is unknown whether Aurthour's frequent bruising is because of his own delicate nature or because Equius is too strong even for monsters. Aurthour's species is said to be one of the strongest kinds of lusus, which is why Aurthour became Equius's custodian; no other lusus could handle Equius's ridiculous strength.

He was killed when the Catenative Doomsday Dice Cascader malfunctioned and blew up part of the rockface that supported the section of Equius's hive. He was in the section of the house that crumpled, and he plummeted to the ground below.

His corpse was then later retrieved from the rubble to be deposited into Equius's kernelsprite.

Gamzee's Lusus
Gamzee's lusus is a giant goat-like sea creature. It had apparently often been out to sea instead of caring for Gamzee as a custodian is supposed to.

It was speared by what appears to be a harpoon or something similar, and died while Gamzee comforted it.

Eridan's Lusus
Eridan's Lusus appears to be a large sea horse. Eridan rides upon his Lusus' back, as it floats or glides through the air. He is also seen hunting with his Lusus serving as a noble steed.

He is the only Troll to accessorize his Lusus, equipping it with a violet saddle and reigns. Within the privacy of Eridan's hive, his lusus does not wear riding gear.

Feferi's Lusus
Feferi's lusus is a colossal, squid-like abomination that dwarfs all other Lusii by a massive degree known as Gl'Bgolyb. It is also known as "The Rift's Carbuncle", "Emissary to the HorrorTerrors", or in more hushed tones, "Speaker of the Vast Glub".

Feferi appears to feed her Lusus with the whales, and perhaps other suitable lusii, that Eridan hunts and kills. The monstrous lusus makes a whale seem like a gnat in comparison to the smaller of its two mouths.

According to Feferi, her lusus whispers to her. Some of what she whispers are prophecies, including that of the world's end and of uniting the two Troll races. She loves her lusus very much, although she has expressed that "keeping her voice down" is a burden to her. She does this by feeding her the dead Lusii of other trolls. If Gl'bgolyb's voice is ever raised above a whisper, trolls would start dying, the psychically susceptible lower castes first, and if raised to a shout, every troll on the planet would perish. But if she were to ever get "really upset", she might release "the vast glub", a psychic shockwave that would exterminate every single troll in the galaxy.

Other Lusii
The Lusii of other trolls have been seen, all of which had been killed by Eridan to feed Feferi's gargantuan Lusus. Among these Lusii have been a flying, cloud-dwelling whale with Gamzee's blood color, and various other reptillian or serpentine Lusii with varying blood colors. These Lusii are shown briefly, and aren't going to have much relevance in the overall plotline.