A prominent figure in the field of Nursing Science, Callisto Zacchaeus became an activist in primate liberation after completing their tenure at Banebridge Military Institute of Mensa. Having lived life among the Pioneer caste, Callisto had helped to settle many new colonies in the galactic frontier, but decided to find a new purpose helping others with the Doctors. Now, with the fate of the Earth primates in the balance, Callisto hopes to right the wrongs that were borne upon them by the Homo Insipiens.
