Written by Bert Van Vliet, Bubblegum Zone is a self-insertion fanfiction set in the Bubblegum Crisis anime. There have been eleven episodes (numbered 1 through 10, with an episode 2.5 written out of sequence), a revengefic where the Knight Sabers (including Sky Knight) take their revenge on Bert for what he puts them through in the story; and a divergent section that crosses Bubblegum Zone with Twisted Path. There is also a spinoff fanfiction, Three Knights, that crosses Bubblegum Zone with Bubblegum Avatar and Bubblegum Crisis: The Next Generation.
The protagonist of the story is of course, Bert Van Vliet, dubbed the Sky Knight, a somewhat chivalrous and often reckless young man. The bulk of the story covers the events of the original anime from the second episode through Bubblegum Crash, with the addition of Sky Knight and of his nemesis, Hollister.