I have done some research into the connections between the Halo and Marathon series. Nothing serious, just some basic lookups, a little light reading of forums of peoples opinions, and I can't help but notice a constant in all three games. An ancient incredibly advanced yet mysteriously gone alien race. In both Pathways and Marathon, it is called the Jjaro, in Halo, its called the Forerunners. It is speculated that in Marathon: Infinity, the protagonist is flung between different realities trying to keep the Jjaro being W’rkncacnter from awakening. Durandal was obsessed with trying to find the secrets of the Jjaro because he believed they knew how to escape the universe. If the Jjaro and the Forerunners are one and the same, then maybe Masterchief and the Security Officer are the same, and Cortana and Durandal are the same, just represented differently in each "reality" Cortana and Durandal are both the names of swords in ancient mythology, the Pfhor's army is comprised of different races through enslavment by the Pfhor, the Covenant's army is comprised of different races through religion. Both are intent on destroying the Human race because they cannot be brought into their fold. The connections are all there. All linked by the ancient race, the Jjaro/Forerunners. This is my opinion, so feel free to tear it apart without any flaming from me.