The main protector of the Shangpa lineage is six-arm Mahakala. All the Mahakalas are a manifestation of the Bodhisattva Avalokiteshvara. Avalokiteshvara is peaceful but when the sentient beings karma is such that peacefulness cannot help them and cannot tame them, then the Buddha manisfests in a wrathful manifestation. Buddha’s manisfestation is not limited. Buddha does not always smile. There is smiling Buddha, there is frowning Buddha and there is Buddha blazing with fire. Mahakala is the blazing Buddha. And this is to help us, to protect us from our own defilements, to help all sentient beings from all obstacles.
We all have a little demon inside us, and Mahakala is to burn that demon, to destroy that demon, and to tame that demon to become a good and kind bodhisattva.
from “Shangpa Kagyu Teachings” by Chamgon Kenting Tai Situpa