
Mega Man Star Force is set in the fictional year 220X, two centuries after the conclusion of the Mega Man Battle Network series. In this time, the focus on internet technology has diminished, and the world is now connected through EM Waves. While cyber worlds and NetNavis still exist in Star Force, humans have become far less reliant on them and no longer use Navi companions, instead turning to Transers. Three massive satellites—Pegasus, Leo, and Dragon—circle the Earth, powering the EM Wave World that surrounds the planet's atmosphere and maintains global connectivity. Normally invisible to the human eye, the EM Wave World can be seen through a special piece of eyewear known as the Visualizer, owned by the series' main hero. Much like the cyber worlds in Battle Network, the EM Wave World is plagued by EM Wave Viruses that disrupt daily life.
Mega Man Star Force features a new protagonist, a young boy named Subaru Hoshikawa, who wears unique "visualizer" goggles inherited from his father. This action activates a specific wave, calling forth a mysterious extraterrestrial entity known as Warlock. Hostile beings from Warlock’s world have arrived to assault Earth, forcing Subaru and Warlock to unite and become Mega Man to combat these threatening forces. In the Leo version, the intensity rises as Fire Leo wields a powerful Flame Burner attack capable of obliterating enemies in its way.