Mahayana Buddhism is filled with a diverse array of Bodhisattvas, deities and devas. Throw into this multitude any number of popular religion idols and a visit t o a Buddhist temple can be quite confusing. Though I have spent my life studying Vietnamese Mahayana Buddhism, I am still a little hazy on a few of the commonly seen images - primary among these being the Dharma protectors that feature at almost every temple.
The fellow at the left is at one of the outdoor shrines at Kwan Yin temple, which is just down the road from my house. The Dharma protectors always have offerings made to them, but you'll find nary a mention of them in any English book on Buddhism.
A monk once told me that these deities are manifestations of Kwan Yin in her wrathful form, there to protect the Buddha Dharma from corruption and destruction. They are always placed close to the entrance of temples in order to deflect any negative attention from the main shrine.
This particular statue is of Wei Tuo Bodhisattva, who is always depicted carrying a sword in order to better defeat ignorance. He is a general and guardian of the temple.
At Minh Giac temple, which is my local, the monk recently converted the backyard barbecue into a shrine to the Dharma Guardians. As you know, Vietnamese Buddhist monks are staunchly vegetarian, and so this inherited backyard feature was never really of much use to them. I'm glad they have found a more appropriate use!