The red ending. Is it canon? Who's to say? It's the only ending that differs greatly from the others and that's for one major reason.
Until now we all thought we knew. There's that final scene that isn't present in any of the other endings. The camera pans up to find shepard buried in the ruins of London, and then right before the scene ends - he gasps for air and the credits roll.
But was it his last gasp? Or the first of many? Does Shepard actually live at the end of the, "Destroy" ending or will fans just be left with even more questions?
You may notice that in the "Shepard lives" ending, the love interest hesitates to place Shepard's name on the wall, and instead looks up as though deep in thought. This is meant to suggest that the love interest is not ready to believe Shepard is dead, and the final scene reveals they are correct. As the Normandy lifts off, there is hope that the love interest and Shepard will again be together.
So there you have it. Shepard is indeed alive at the end of the "Destroy" ending. But what does this mean? Is it the canonical ending? Will we ever see Shepard again? Does any of this matter? Why did nobody care that Weyland was alive at the end of Prometheus?! I want answers!