Its the same universe. The master chief can be found in 1 of the new missions. After our first fight with a shadow of oryx on earth. Looking for invisibility powers. Have a look around. On the right side if i remember corectly. Make sure after you kill the shadow. Dont find the invisibility drive until you have a good look around. Our ghost says. He was the greatest warrior i asked him to wake but he said he has faught his battles