The general accepted version is that the father of the two boys was killed (the reasons differ, but it was probably an argument over land rights) when they were infants.
As adults they became skilled fighters intent on avenging their father and retrieving his sword Tomokirimaru.
In May 1193, the Soga brothers participated in shogun Minamoto Yoritomo's grand hunting event Fuji no Makigari.
The younger brother Tokimune killed all the samurai one by one who attempted to stop him, and broke into Yoritomo's living quarters.
The next day, Tokimune was brought in for questioning by Yoritomo about the motives of the incident, but was ultimately executed.
Like most of these historical stories, it is the result of the compounding of (often differing) versions passed down through an oral or other tradition.
According to tradition they were buried at the foot of Mount Fuji, there is a sculpture of their tombs among the stone statues in Hakone.