Alpha-seijin

The Alpha-seijin were green, reptilian humanoids native to Planet Alpha. Slightly larger than Kid Buu in stature, they built sprawling cities and developed ranged weaponry including arm-mounted ray guns. Their appearance earned them the alternate designation "Lizard Aliens" in the Japanese credits of Dragon Ball Z Kai. Despite their technological advancement, the Alpha-seijin were not warriors by nature; their weapons were defensive tools, not instruments of conquest. They lived in organized urban settlements, suggesting a civilized society with infrastructure and governance far beyond what most alien species in the Dragon Ball universe demonstrate.

The Alpha-seijin never appear in the manga. Their entire existence is conveyed through a single anime-only flashback during the Kid Buu Saga, shown as Kibito Kai recounts the destruction Buu has wrought across the universe. In this brief sequence, Alpha-seijin soldiers are seen firing their ray guns desperately at the approaching Kid Buu. The weapons have absolutely no effect. Buu tears through their ranks without slowing down, kills every last one of them, and then destroys Planet Alpha entirely. The scene lasts only moments, but it accomplishes exactly what it needs to: it demonstrates that Kid Buu is not just a threat to Earth, but an extinction-level event for any world unlucky enough to be in his path.

The Alpha-seijin represent one of Dragon Ball's most effective pieces of worldbuilding through tragedy. They existed only to die, but their brief appearance served a critical narrative purpose. By showing an entire civilization with cities, technology, and organized defense being annihilated in seconds, the anime raised the stakes for the final confrontation with Kid Buu far beyond what a simple power level number could convey. No named members of the species survived, and Planet Alpha was reduced to space dust. They are among the many races permanently erased from the Dragon Ball universe by Majin Buu's ancient and seemingly random campaign of destruction.