The SkyClan Kit

The unnamed SkyClan Apprentice of destiny was a newborn female kit, stolen by Hvitursnow in The Apprentice Prophecy, to be the SkyClan apprentice of the prophecy. Kestrelfang described the kit as being female. She was stolen from the SkyWing camp. After she was killed, she was replaced by Glorystar.

Pre-Series
In the prologue of The Apprentice Prophecy, Hvitursnow was caught by Burnscar after stealing the SkyClan kit from the SkyClan Camp. Burnscar toyed with the kit while the chained Hvitursnow, kept from using his frostbreath, pleaded for its safety. She feigned consideration, then dramatically dropped the kit over a tall cliff before she gruesomely killed Hvitursnow. The prophecy could not have been fulfilled without five dragonets, so Webstail, the SeaClan guardian, stole a RainClan kit to fulfill the prophecy. However, the guardians always viewed Gloryfang as a replacement afterward and treated her terribly since she was not a SkyClan apprentice as they had wanted.

Kestrelfang, the SkyClan guardian, later found the corpse of Hvitursnow and the broken kit’s body at the base of the cliff. Kestrelfang wouldn't have minded if they had this kit, saying she should've stolen it herself, claiming, "They wouldn't have caught me a second time."

Later books
The SkyClan kit was mentioned frequently as the dragonets talked about how Gloryfang replaced them. Kestrelfang mentioned that a SkyClan cat would have been better than Glorypaw many times before her death in The Dragonet Prophecy, and Glorypaw frequently wondered whether a SkyClan apprentice would have been better. After the events of The Dark Secret, Sunnyday wondered why everyone was so mean to Glorystar about not being the SkyClan apprentice if the prophecy was false.