A warrior is a living shrine (avatar) of the divine,
one who serves the grand purpose.
O'Sensei never attributed his great martial and spiritual power to himself. He said he was a conduit for the kami to flow through him.
Ancient Kemetic (Egyptian) texts talk about cutting-off one's head and replacing it with the head of a god. This was symbolized by putting own an animal head. This is why you see so many of the gods in the ancient Kemetic pantheon with the heads of animals. The animal heads were metaphors of various divine attributes. Similar to today where you have expression like one being hawkish or stubborn as a bull.
Cutting-off one's head is a metaphor for the detachment or worldly things spoken of in Buddhist dogma. One must not let one's own desire, one's ego-shell, rule over ones action. This is a very difficult concept for those raised under a western paradigm where the individual is king, where segragative (dualistic) logic dominates and holistic (synchronic) thinking is seen as new age propaganda. I speak of this because one cannot gain access to divine power without separation one's True Self from one's persona.
People like O'Sensei, Mother Teresa, the prophets and the saints where able to accomplish great things not because of there own personal power, but because they sacrificed themselves to the greater good, to the Divine. If one aligns one's will to that of the Divine Will, nothing in heaven or earth is beyond your power, but if one is aligned to the Divine one seeks to control nothing of desire nothing. One must become dead to the world and born again.
Lesser effects are possible through pure psychic potential (ki development) and hedge magick where through mental and auric induction one can cause changes to occur in the material plane. Although, I feel that one should develop ones own personal ki as much as possible, it has limits and no moral constraints. As one develops one's personal ki he should subscribe to a philosophy, similar to that in aikido, and strive to align one's personal ki to the Universal Ki.
I hope I haven't gone too far off the topic, and I think in a round about way it answers your query.
Peace and Blessings (Used the Force Luke.