Sprite

The Kernelsprite is an entity released when a Sburb player first opens his or her Cruxtruder. At first, Kernelsprites are nigh-on-useless, unintelligible balls of light (the Kernel). In order to be useful, they must be prototyped, which involves dropping an object (that is absorbed indefinitely) into the Kernelsprite. They are said to be "drawn", in a sense, to the dead or soon-to-be-deceased - there is no explicit rule saying that a Kernelsprite must be prototyped with something dead, but across all sessions ever played, almost all of them are. These objects' characteristics determine the sprite's personality and abilities. Sprites can be prototyped at least twice (so far no one has attempted to prototype them a third time), and at least one pre-entry prototyping is necessary to win the game, presumably because Skaia would otherwise be unable to grow to its final form.

A properly prototyped sprite is given access to a wealth of knowledge about Sburb, but there are apparently limits on what a player's sprite can tell them and when, and sprites are supposed to be coy in nature. Davesprite, however, decides this is all nonsense and agrees to tell the kids anything they need to know.

Sprites cannot accompany their players through the first gate. Players unlock the power to have the sprites accompany them through the gates at a later point in the game. John and Rose have unlocked this ability in the form of special pendants given to them by Nannasprite and Jaspersprite.

Prototyping
Prototyping is when a kernelsprite is "merged" with an item taking on certain similarities. Upon entering The Medium a prototyped kernelsprite will divide into two, carrying the data of the item(s) that prototyped it to Prospit and Derse. Not only is the kernelsprite modified with the data, but also the denizens of the kingdoms. For example, John Egbert prototypes his kernelsprite with a Harlequin doll, resulting in imps and ogres with colorful harlequin outfits. The imps also seem content with just causing a ruckus instead of defeating John. It should be noted that the traits the sprites inherit from post-entry prototyping have no effect on the medium. Therefore, none of the imps have traits akin to John's grandmother.

Kernelsprites require one pre-entry prototyping. Before prototyping, the kernelsprite is unintelligible. It only communicates intelligibly after it's prototyped with a living or once-living creature, and its intelligence appears limited to that of its composing parts. Rose's Jaspersprite is notably less adept at conveying concepts than John's or Dave's sprites, although it seems to have been granted enough intelligence to be able to talk to her (although Jaspers may not have been an ordinary cat while alive). Dave's Calsprite... well, let's not go there.