Get a banshee in last level. Fly to the right of the building when the door is busted. Go towards bottom right and you should get the cutscene with Tartarus. You can then fight him.
In Convenant Holy City, reach first outdoor area with dirt and vegetables. Turn right, run to the wall past the gravity lift. Follow top of wall
At outskirts, jump up the ruts in firs twall, then jump on roof and go to left. Should be next to camera
In Arbiter level, go to end and fly down in the banshee. It is hard to see but Grunts are dancing around it
On last Chief level, in Final lift, look up
AT start of Quarantine, go through tunnel, then carefully walk along ledge
Complete game on any mode after taking Banshee in last level
Finish on Legendary
Beat game on easy, then hard in 3 hours
Find on Regret, after first lift ride, grenade jump from first awning to ledge in front of you
Enter ".fortune" as profile name