Princess Royale - a sci-fi, young-adult story by Albert Ruckholdt

On a terraformed world in the far future, a high-school student survives a brush with death, and finds himself forced to compete as a girl – a Gun Princess – in a brutal tournament known as the Princess Royale, where the stakes are high and victory is achieved through the barrel of a gun.
A high-school battle gender bender action comedy.

Ditched after class by his best and only friend in favor of a date with a hot girl, Ronin Kassius distracts himself from his woes by enjoying an afternoon of zombie killing at his favorite gaming arcade. But after being ordered home unceremoniously via text message by his elder sister, Ronin witnesses a strange phenomenon sweep through his surroundings, leaving him in a dead and deserted city. There he encounters a doll-like girl in strange armor, and soon experiences his apparent death when his body decays and crumbles away.

Returning to school the following week, Ronin decides it was all a dream, until a strange voice in his head, belonging to an entity calling itself a Maestro, informs him that he died and is now living in a temporary body. To get his original body back, that is being stored for eventual regeneration by his mysterious benefactor, Ronin must fight in the Princess Royale, a brutal spectator sport fought out in Slivers that are copies of his reality serving as arenas.

However he won’t be battling as a man but as a girl, a Gun Princess by the name of Mercedes, and a special existence that can survive in the Slivers without decaying.

With his Maestro nicknamed Jive as a guide, instructor, tormentor, and confidant, Ronin must learn to master Mercedes's body and compete with other Gun Princesses for the title of Gun Queen – or he may never get his real body back.