Jadesprite is Jade's sprite, created by second-tier prototyping Becsprite with the corpse of her dream self. As a result, she has first guardian powers, but she is unable to stop seeing the Green Sun.
Immediately after being created, she breaks down and destroys the tower holding up the lab, sending it rolling down on to LOFAF. She claims to have been in some sort of afterlife where she met her “friends”, and is upset at being taken away from them.
Jade originally hoped that her prototyped dream self would be able to fight Bec Noir with first guardian powers. However it quickly becomes clear that Jadesprite is as emotional and forgetful as Jade's dreaming self was. Her first conversation with Jade dissolves into sobbing almost immediately. She is only interested in getting back to the friends she made in the afterlife. Any other plan seems completely hopeless to her, especially one as far-fetched as sending a disoriented and emotional wreck of a sprite to fight Bec Noir. When Jade's dream self died her grandfather preserved the corpse and took it with him back to a time on Earth before the kid's session even started. From Dream-Jade's perspective she was dead for years and has long since moved on from the concerns of her waking self. She is completely ignorant of everything that happened after her death and has forgotten most of what happened before it. Jade quickly becomes frustrated with Jadesprite and launches into an ineffective and foul-mouthed tirade. Karkat compares these arguments to his own fights between his past and future selves.
Sometime shortly before the scratch Jadesprite is seen moping about the Battlefield, plagued by guilt and insecurity over her uselessness to her still-living friends, and encounters a battle-scarred Davesprite. Davesprite is fresh from an encounter with Hephaestus and has obtained a repaired Royal Deringer. This prompts a conversation about what the kids are doing, the true purpose of the Denizens, and the choices they give players. With Davesprite's encouragement Jadesprite then sends the Royal Deringer to Dave Strider on Derse with her first guardian powers.
In [S] Cascade Jade ascends to god tier, subsuming her sprite-dream self and ending Jadesprite's brief stint as an autonomous individual. This also allowed Jade to acquire her spriteself's first guardian powers from having been prototyped with Becquerel in addition to her Witch of Space god tier powers.
During the journey across the Yellow Yard Jade mentions her memories of being Jadesprite are vague but also mentions that during the time her dream self was dead she became friends with a group of unfamiliar trolls.