The Four Gomas aka Four Gatekeepers work to protect sentient beings.
The White Goma stands at the eastern gate of the mandala and carries a hook that catches evil spirits.
The Yellow Goma stands at the southern gate of the mandala and carries a rope that binds the evil spirits.
The Green Goma stands at the northern gate of the mandala and carries a bell that she rings to drive the evil spirits so mad that they cannot escape.
The Red Goma stands at the western gate of the mandala and carries an iron chain that is also used to tie up evil spirits.
