The statue is called Kongō Rikishi (Skt. Vajrapāṇi) as a tutelary deity in the Buddhism. The comical appearance with bushy beard gives a cheerful impression and represents as an exceptional example. It may have been categorized into the eight century sculptures. However, the place of fabrication is still under discussion, suggesting either in Japan or in China.
 
Yasuo Inamoto 
Masterworks from the Nara Buddhist Sculpture Hall at the Nara National Museum. Nara National Museum, 2010, p.136, no.167. 

 Kongō-rikishi (guardian deities) are usually made as a set of two statues; the one with the open mouth is called "Kongō" and the other one with the closed mouth is called "Rikishi". This is the Rikishi statue with angry face and its mouth closed. The right arm stretches downwards clenching the fist, whereas the left arm is held in front of the body and the five fingers of the hands are stretching. The upper half of the body is naked, and the lower half is covered with drapery. The statue is standing on the lotus seat in a dynamic pose: the string of the topknot and stole are waving, and the big toes are lifted. It was made in the dry-lacquer method with the body painted red. This style of Rikishi statues standing on the lotus seat was not common, and there are only a few extant examples of them made during the Hakuhō period. Lines across the forehead, widely opened eyes and the extensive brush-like beard catch people's eyes. The muscular body and the manufacturing method of the statue indicate that it was made during the first half of the 8th century. 
Masterpieces of Nara National Museum. Nara National Museum, 1993, p.13, no.4.