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 into the Kernelsprite (losing that object forever). They are said to be "drawn," in a sense, to the dead or soon-to-be-deceased - while there is no explicit rule saying that a Kernelsprite must be prototyped with something dead or doomed, 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, Rose, and Dave have unlocked this ability in the form of special pendants given to them by their sprites.

The Trolls' Lususprites were all killed, presumably by Jack Noir or something else related to The Scratch. It is unlikely that they were disposed of by the game itself, as Aradia remains in sprite form.

Prototyping
Prototyping is when a Kernel is "merged" with an item, taking on certain similarities, turning it into a Kernelsprite. Upon entering The Medium, a prototyped kernelsprite will divide into a Kernel and a Sprite, The Kernel will also divide in two, carrying the data of the item(s) that prototyped it to Prospit and Derse. So, 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. These traits appear instantaneously; they are not limited to underlings created after the Kernel splits.

Kernelsprites require one pre-entry prototyping in order to successfully evolve the battlefield to its final form, which is necessary in order to allow the Genesis Frog to grow. A session with no pre-entry prototyping is called a Void session. A lack of orbs on a session's Prospit and Derse (as well as the Queens' rings and Kings' scepters) are indicative of a Void session. The post-Scratch session is a Void session as shown from the HS 6290 (lack of Prospitian) HS 6386 (and Dersite orbs.) When HS 6565 (Jane entered), God Cat prevented her sprite from being prototyped, and Jane entered the medium without having done so.

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 (or perhaps Jaspers was not an ordinary cat while alive). Dave's Calsprite... well, let's not go there.

Appearance
A sprite has two forms: the simple form (like John's harlequin sprite before entering the Medium) and the ghostly form (like John's sprite after entering the Medium). There seems to be no consistent rule with the sprite's appearance, since the kids' sprites alternate between those forms.
 * John's harlequin sprite was in simple form before entering the Medium, then ghostly form post-entry.
 * Rose's Jaspersprite was in simple form before the tier-two prototyping.
 * Dave's sprite follows the rules for John.
 * Jade's sprite was never in simple form.