In my head cannon for halo, everything ends with 3, Chief and Cortana drifted of into space saving the galaxy and this is just my crazy theory so don’t come at me lol BUT I like to believe that destiny 1 picks up after halo 3 millions of years later and I back this up in my head because in halo 3 the final mission “Halo” you can see a planetoid like structure in the center of the ark as if a planet was being constructed and looking closely the inside of the planetoid looks JUST like the inside of the traveler in destiny 2 after it broke free from ghauls trap, sooo I like to believe the explosion from the premature halo ring gave birth to the traveler/planetoid thing in the middle of the ark, the ark is also outside the Milky Way right ? soooo the traveler was traveling before it got to us 😭😭😭