Guardian Kings (Myôô)
Guardian Kings (the smaller figures at the bottom of the image above): ferocious native deities (often associated with the Naga Dragon Kings) who converted to Buddhism and now act as "body guards" for Buddhist deities, guarding the four directions plus the center. They are understood as manifestations of Dainichi Nyorai, the Great Sun Buddha.
Niô, guardians of the gates to a Buddhist temple. How are these two statues complementary?
Image of a ferocious native deity prior to "pacification" by Buddhism
Image of Yasha (demon) from the Yasha Gate (Yasha-mon) at Daiyuin-Byo at Nikko
Image by John Harvey from <http://www.johnharveyphoto.com/Japan2/Nikko/Yasha.html>