A large, strange creature that Reira grew from the materials of a quest given from Mana. She had requested a pet who would be able to come with her in the skies, the waters, and even underground- what she received is something resembling a large, trunked seal, with a glowing lure appendage on its head.

It has no eyes, apparently navigating through vibration and sound, and seems to have no mouth... ...in actuality, it has many; they can reveal themselves without warning as numerous lamprey-like openings, capable of eating rocks.

Incidentally, rocks are Lusus' favorite meal.

Lusus was so named because of a form of Vriska that Reira knew; due to the 'eleseal's white coloration, she mistook them for a 'Lusus'.

Notably, Lusus doesn't seem to like anyone other than Reira... ...and oddly enough, Doppio.