Locker Balls, or Planet Crystals (星の結晶 Hoshi no Kesshō?), are small star-shaped devices that are able to execute a program left behind by the warrior god, Fudo Myo-o, which controls the binding and splitting of matter. The program has the power to connect the molecules that comprise solid matter, and to control the gravity emanating from H-Particles. Those who master the program undergo a metamorphosis, fusing with the device and becoming a Samurai, gaining those very abilities. When a Samurai dies, their body reverts back into a Locker Ball.
Locker Balls are found scattered across the universe, often deep inside the cores of planets. They can be sensed by Princesses, who act as caretakers for the Locker Balls and their "Samurai of Fate," the individual destined to merge with it.