Does he pull an old man Biff and goes back to 1955 rewriting an alternate 1985, or does Marty chase after him and goes to 1955?
hmmm
Since they're the Iron horde now, I am guessing he arrived a few yrs prior to "us" getting there. Or either it will be like MoP where they're being brought up and by the end of the expansion the iron horde are well established threat.