: I thought about the idea of halo and marathon being connected in that
: marathon was in story older than halo but I finally thought you know what
: halo is a remake of marathon it explains the rampant AI ( Durandal Cortana
: ) the weapons the ships the aliens the factions of aliens it all makes
: perfect sense that halo is a remake of halo that is more stylized
Maybe there's some inspiration there, but nothing direct:
Q: Is Marathon the prequel to Halo?
A: No, Marathon is a separate story, with wholly different characters, story and gameplay.
Q: Are the Pfhor related to The Covenant?
A: No, although they do share some traits –such as enslaving client races, they are entirely separate and each exists in a different "universe."