He was not Anunnaki, nor of that lineage among the human bloodline created through the interbreeding with human females. He was simply an extraordinary person in such divine alignment he possessed a nearly perfect genetic endowment enabling him to fully express the potential within him by virtue of his ethnic heritage, a robust health, and being predisposed to having a large frame and exceptional stature. This was prearranged to happen in keeping with his being on a divine mission life to be noticed and to be effective as an example of divinity and what it can accomplish by people cultivating a divine partnership.
He was certainly an example of the benefits of being in divine alignment, not because he came from a dark lineage, but because he had avoided serious complications by not aligning with the darkness and was the beneficiary of much good karma and effective divine planning in the light prior to his incarnation. And this gave him much to work with and many blessings along the way to overcome errors and mistakes and to parlay that capability to become an iconic figure revered by subsequent generations of people looking to him as an example of the possibilities of goodness and its power.