Lusus

Also known as Lusus Naturae, the custodians are the Hivebent equivalent to a Guardian. They look after the young trolls whilst the adults beseige 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. Karkat Vantas' lusus is some sort of Crab Scorpion beast that towers over him; it will probably become a part of his kernelsprite. Trolls sure are weird.

Terezi Pyrope/GallowsCalibrator apparently doesn't have a custodian... yet. In her own words, "1F 1 3V3R D1D H4V3 ON3 1T WOULD M34N TH3 WORLD W4S COM1NG TO 4N 3ND."...