Fudo Myoo is a bodhisattva who protects the Buddha Dharma (universal teachings) from evil. Clearly anyone who fears the gods would fear this vanguard.
He holds in his right hand the Vajra; diamond / thunderbolt Sword. Its double edge cuts through self-ish delusion; greed, anger, and ignorance revealing true self-less reality; generosity, compassion, and wisdom.
In his left hand he holds the rope to bind evil.
Art is symbolic.