For almost 30 years the battle between the forces of humanity and the Convenant, an aggressive collection of alien species, has raged across the galaxy. Countless moments of bravery and danger have made heroes on both sides of the war, but above all others stand the Spartan super-soldiers and their leader: the Master Chief, John-117.
Jacob Keyes: Daring and courageous in battle, Keyes was a decorated officer who was often responsible for covert and highly dangerous missions. His combat tactics and intense focus became a standard for UNSC officer training. Unfortunately once infected by the Flood, his fate was sealed.
Prophet of Truth: Shrewd and scheming this politician rose to the rank of Hierarch, a prized Covenant leadership role. The Prophet of Truth's hatred of the human race and his plot to destroy it was eventually foiled by the discovery of the Halo rings and the truths they revealed.
Cortana: The artificial intelligence or 'AI' Cortana was originally designed to infiltrate the Convenant and capture one of their Prophet leaders. This plan changed when the planet Reach fell, and Master Chief was entrusted with her safekeeping - the two developed a deep bond soon after.
Master Chief: Abducted at the age of six, John was conscripted into the Spartan-II project, trained, and augmented to be a super-soldier. A hero and a legend, the Master Chief John-117 changed the course of human history and the universe.