(Capcom's primary storyline)
The Stairway of the Sun, also called Sonnentreppe in German, is a flowering plant in West Africa found deep underground in the Sun Garden. It is of the plant family Asteraceae, which includes such flowers as the Chrysanthemum. This plant naturally hosted the Progenitor virus, but only in certain conditions in which the plants thrived: a cave.
The Ndipaya tribe worshipped the flowers as a purpose of choosing who is worthy of being their leader. Whoever survived after eating from the flowers, would inherit great strength -or so the legends say.
After the Ndipaya tribe was driven out of their lands by Umbrella Corporation , the flowers were harvested by Umbrella to extract the Progenitor Virus. Multiple attempts were made to reproduce the flower on US soil for ease of research, although all attempts resulted in subjects lacking the virus, forcing Umbrella to keep an iron-clad grip on their control of the region.
After the fall of the Umbrella Corporation, ownership of the region was acquired by Tricell, Inc., who continued to research the viral legacy started by Umbrella.