The backstory for the toy sets was detailed in associated media, including an online comic and a series of story books.

The toy line was produced in waves from 2006 to 2008 and was accompanied by a series of story books and 40 issues of the Exo-Force online comic, which was released between November 2005 and March 2008.

Exo-Force centred on a group of elite human pilots that were tasked with defending their home from drone machines that were under the control of a robot named Meca One.

Each member of the group piloted unique mecha weapons to battle the robots and then travelled to the enemy base to rescue their leader.

As part of the financial recovery, the company aimed to create original themes that would appeal to children and adults.

Due to the rising public interest in Japanese anime during this period, which was driven by shows like Dragon Ball Z, Pokémon, and Yu-Gi-Oh, The Lego Group made the decision to create an original anime-inspired theme.

The 2007 storyline centers around Exo-Force's discovery of the legendary Golden City at the top of Sentai Mountain and mysterious secret codes therein which could be used to unlock powerful technology.

The remaining Exo-Force pilots must rescue their leader in this hostile jungle environment that holds the secret to what gave the robots life and the will to destroy.

[2] The minifigures in this theme were created with a unique style that included cartoon-style hair pieces and anime-style faces.

[2] These promotional sets were released in Europe (e.g. packaged with Donald Duck magazine in Denmark) and are not part of the main toy line.

The Lego Group developed a series of long-format commercials composed of two-minute episodes that aired on Nickelodeon and Nicktoons during late January 2006.