Alexander Yamato studies at Schwarz Rose Academy, training rigorously to become a Prism Star. He proudly embraces his reputation as a "Prism Show vandalist" and "street tyrant," championing raw street-style prism performances while scorning idol-style shows. Physically, he towers at 190 cm with short green hair shaved on the sides, violet eyes, and a dark complexion. Multiple earrings adorn his ears—four on the left, three on the right—and he wears a neck chain.

Born June 6, Alexander is 16 during *King of Prism by Pretty Rhythm* and 17 in *Shiny Seven Stars*. His personality flares with aggression and a fierce temper during street-style prism competitions, yet he reveals unexpected politeness toward respected figures like Rei Kurokawa. Kazuki Nishina stands as his ultimate rival; Alexander relentlessly pursues Kazuki's "street charisma" title. This rivalry fuels his prism battles, clashing violently with Taiga Kougami due to mutual disdain.

In *Pride the Hero*, Alexander sabotages a performance to disgrace Kazuki, triggering a prism duel where Taiga defeats him. This defeat sparks a shift: Alexander eventually accepts Kazuki’s belief that authentic audience connection outweighs performance style. By *Shiny Seven Stars*, he works at Prism Stone alongside his Pair Friend, the dragon Dorachi. He competes in *Dramatic Prism.1*'s PRISM.1 championship, featuring new prism sequences, though specific event details are unrevealed.

His name, Alexander, stems from Greek for "defender of the people," while Yamato fuses Japanese characters for "great" (大) and "harmony" (和).