In the upcoming game Halo 5: Guardians, Master Chief’s former teammates are finally getting their long anticipated appearance in a Halo video game. But, by including the members of Blue Team in the game, 343 Industries have thrown the entire Halo canon out of equilibrium. Spoilers for novels and Halo:Reach.
Back when Halo: Combat Evolved was released in 2001, a tie-in novel called The Fall of Reach filled in the Master Chief’s backstory. We learned of his origins in the Spartan-II program, and we were introduced to the members of his squad Blue Team, namely Fred, Linda and Kelly, as well as his AI companion, Cortana. As we learned in the game, all other Spartans were presumed dead after the planet Reach was destroyed. But, in the sequel novel, First Strike, we learn that Blue Team manage to survive the Battle of Reach by withdrawing into a Forerunner structure deep beneath the surface with the creator of the Spartans, Dr. Catherine Halsey. In the subsequent novel, Ghosts of Onyx, Dr. Halsey learns of a secret Spartan-III program that used her research to create expendable Spartans for impossible, suicidal missions.
This was all well and good, until the release of Halo:Reach in 2010. In that game, the developers Bungie shows us a completely different backstory to the Battle of Reach, Dr. Halsey and the Spartans. In that game, the protagonist is a Spartan-III, part of a fire team that is entirely at odds with their depiction in the novels. Dr. Halsey appears in the game as well and, unlike in the novels, she is fully aware of the Spartan-III program. Later on in the game, she calls the main characters down to the Forerunner ruins, where she gives them Cortana to bring to Master Chief. According to the game, Cortana was only just finished there, and this was to be her first assignment. In the books, meanwhile, Cortana had been active for quite some time, and knew the Chief. Towards the end, one of the Spartan-III’s flies off with Dr. Halsey to an unknown fate, while your character carries out the mission to bring Cortana to the Master Chief.
As a game in a primarily video game series, Halo:Reach presumably takes precedence over the tie-in novels, and as such retconned the events of the novels. However, now that the members of Blue Team from the novels are being brought into the games, it has thrown everything up into the air. To people who have not read the books, the events of Halo:Reach would be canonical, but those of us who have read the books and comics must now take them as the correct telling of these events, and not the game. To further complicate matters, the Spartan-III who, in Halo:Reach, flew off with Dr.Halsey showed up again in the comic Halo:Initiation. As it stands, there are now two wildly differing versions of events for the same pivotal moment in the Halo lore. Unless Halo 5 does something to clean up this mess and clarify things, the Halo fandom will remain fractured in two.