Well, Yin-Yang is called Tao and in Ramayana you will find the following:

Once Lord Rama asked Lord Hanuman, “How do you see me?” And Lord Hanuman replied, “When I see myself as a body, then I see myself as your faithful servant. When I see myself as the soul, I see myself as a part of you. And when I see myself as Absolute, you and I, my Lord, are one and the same.”