|This article is about a/an planet in Kamen Rider Build.|
Planet Blood (ブラッド星 Buraddo Sei) is home to the evil alien clan Blood Tribe, the most notorious member of whom is Evolto. It was destroyed by Killbus, the King of Blood Tribe. It is also the point of origin of the Pandora Box, an extremely powerful weapon used by Evolto and his kind to wipe out numerous other civilizations across the universe. The last two worlds struck by Evolto were Mars and Earth, the inhabitants of each remaining unaware of their assailant's homeworld.