Mangatsu Temple is right next to the Usuki Stone Buddhas. The current buildings date from 1950 though it was established in the Muromachi Period.
The Nio are quite interesting, and like the torii at the entrance to the little valley, are now buried up past their knees, no doubt from centuries flooding leaving layers of silt.
It is now a Shingon temple though if that was its original sect I don't know. It was supposedly established by Renjyo, a Chinese monk who it is said was brought over by a local man Mana no Choja and his wife "Princess" Tamatsu.
Behind the temple are a pair of statues of the couple as well as this one of Renjyo. It is said Mana no Choja financed the carving of the Usuki Stone Buddhas.