Despite wanting a quiet reborn life, this former college girl levels up to the max as the villainess.

One summer day a group of sixth-grade boys have an argument about whether fireworks are round or flat when viewed from different angles and embark on a journey for the answer during the annual firework festival. Meanwhile, one of their classmates, Nazuna, is troubled by her parents' separation and decides to choose one of the boys - Norimichi or Yuusuke - to run away with depending on who wins a race at the pool.

Ichiban Ushiro no Dai Ma?, also known as Demon King Daimao, is a Japanese light novel series written by Shotaro Mizuki and illustrated by Souichi It?, published by Hobby Japan under their HJ Bunko imprint. The first volume was published on February 1, 2008, with a total of 11 volumes available as of December 2010. A manga adaptation began monthly serialization in the September 2008 issue of Akita Shoten's magazine Champion Red, and a 12-episode anime adaptation by Artland aired between April and June 2010 on Tokyo MX and other channels.