In a movie full of surprises (some of which, like the death of Loki in the first ten minutes, or the death of nearly everyone in the last ten minutes, left fans, to paraphrase Spidey, "not feeling so good") the unhinted at appearance of Red Skull in Avengers: Infinity War as the guardian of the Soul Stone was a bit of serendipity that was quite welcome by comparison. (This is not at all to say that we don't understand why the Russos had to raise the stakes in Infinity War, but gah! It hurt!).
Just to backtrack a bit, when we'd last seen Red Skull in the MCU, it was way back in 2011 (or the 1940's, depending on which universe we're talking about) when he was featured, of course, as the villian in Captain America: The First Avenger. After his run in with the Tesseract (aka the Space Stone) in that film, poof! he's gone, only to turn up again in Infinity War, 70-something years later, surprise, surprise, hanging out in exile all anti-Luke Skywalker-like on Vormir, complete with the requisite exiled-on-a-planet hooded cape, trapped in his new role as the keeper of the Soul Stone.
And, what with everything else going on, that was the last some of us thought we might see of him. Until, late last night, the Russo Brothers tweeted out this in response to a fan's question, "Now that the Soul Stone has been taken, is Red Skull free to leave Vormir?"
What?? Pursuing an Infinity Stone of his own? Again? Yowzers! What with all the talk of Ant-Man and the Quantum Realm, and Captain Marvel to the rescue, and who will or won't be brought back from the fingersnap of death, I for one hadn't even thought about Red Skull since Vormir. Looks like Avengers 4 is going to be one helluva ride.