Wakan is will, the force of will, action in the world. "Wakan is not a mystery, something ethereal to be worshipped in the abstract. When Black Elk sings the western grandfather's song for Neihard--"The thunder nation is appearing, may you behold" -- his words reflect the emergence of warrior energy in the people.....Black Elk...learns that instead of passively receiving protection from the spirits, the must seize the power to live." It is the warrior energy, the power available to all people to take responsibility and act/change the world. The will and energy to change the world. The warrior's job, in addition to defense, is to invoke wakan energy in the people.
Wakan is a basic principle, antagonistic to notions of the "Great Spirit" which "was either a missionary imposition or an oversimplification of Lakota belief offered by elders attempting to explain their spirituality to non-Indians. When a person prays, he or she must already have a firm resolve and a basic plan. The spirits can only supply the tools, not the will or the purpose, and man must initiate the relationship." 
Though wakan is usually translated as 'holy,' 'sacred,' or 'mysterious,' and Wakan Tanka is usually taken to mean 'Great Mystery or 'God,' the term probably [means] an all-suffusing cosmic energy obtained through personal visions." <ref>c.f. Fabric of Consciousness.
- Rogers, Spencer L. The Shaman: His Symbols and His Healing Power. Illinois: Charles Thomas Publishers, 1982.
- Rice, Julian. Before the Great Spirit: The Many Faces of Sioux Spirituality. University of New Mexico, 1998. p. 23 https://amzn.to/2C9fM5E.
- Rice, Julian. Before the Great Spirit: The Many Faces of Sioux Spirituality. University of New Mexico, 1998. p. 29.
- Rice, Julian. Before the Great Spirit: The Many Faces of Sioux Spirituality. University of New Mexico, 1998. p 21. https://amzn.to/2C9fM5E.