|The following information is from the Adventure Time comic book series. It may not be part of the same canon or continuity as the animated series.|
Adventure Time Vol. 11: Princess & Princess is the eleventh graphic novel in the Adventure Time series.
Finn temporarily becomes Princess of the Rock Kingdom as a favor for Rock Princess, inadvertently starting a war.
When Finn is asked to kingdom-sit for a neighboring Rock Princess, he’s excited to take a break from his responsibilities back home, until the Underground Kingdom turns to him with pressing matters. Thrown into the role of ‘princess’, Finn’s adopted kingdom decides to declare war on Princess Bubblegum!