There are two levels of Halo fandom.
The first, lower level, consists of those who've played all of the franchise's major titles - ploughing through the campaigns and ruining their sleep patterns with multiplayer.
The second level is made up of fans who've done this - and then gone out to buy the books, comics, soundtracks and wider story that surrounds the Halo universe.
It's this second bunch that knew who the Didact was when he first appeared in Halo 4, while the rest of us swiftly Googled him in confusion - and it's this lot who'll understand who Blue Team are.
The latest cinematic to be revealed for Halo 5: Guardians sees Master Chief (we all know him) joined by his close-knit Spartan squad, the Blue Team. They're off on a mission to board a derelict Office of Naval Intelligence ship and ensure that no technology falls into rogue Covenant hands.
We're sure it'll all make sense in the long run... right?
Halo 5 arrives on Xbox One on 27 October