Ō clan

Ō clan is a descendant clan of Jimmu and Himetataraisuzu-hime. They are descended from Kamuyaimimi.
Ō no Yasumaro was a famous member. He became head of the clan in 716 around the time he wrote the Kojiki.

Relationship with Takemikazuchi

Takemikazuchi was originally a local god revered by the Ō clan, and was a god of maritime travel. However, the Nakatomi clan who also has roots in this region, and when they took over control of priestly duties from the Ō clan, they also instituted Takemikazuchi as the Nakatomi clan's ujigami. Or so this is the observation by in his Jinja to kodai ōken saishi. He goes on to theorize that the Ō clan was originally ōmi, but was usurped by the Nakatomi who were among the "lesser priesthood".