Until such time as science figures out immortality, there must come a time when actors stop playing their most famous characters. Right now pretty much every actor in the Marvel Cinematic Universe who has a speaking role is synonymous with their character. Chief among them is Tom Hiddleston, as the MCU’s top villain, Loki. Eventually, the day will come when he too must hang up his horned helmet, and according to the actor, that day may come sooner than we think. He seems to think he’ll be done after next year’s Thor: Ragnarok.

While the MCU has created a slate of standout heroes, its work on the villain side hasn’t been quite as strong. This makes the mere thought of Tom Hiddleston finishing up the role of Loki mildly terrifying as there really isn’t anybody else to replace him with. (No offense, Thanos.) However, in an interview with The Daily Beast, Hiddleston isn’t coy in saying that he’s looking forward to Thor: Ragnarok, in part because it will be his last time as Loki.
Thor 3 will be cool because I’ve not done it for four years. I love working with Chris [Hemsworth]. This will be my last time out of the gate.
It’s actually a little hard to believe that it’s been nearly four years since we last saw Loki in Thor: The Dark World. He’s left such a lasting impression on fans, it hasn’t seemed like it’s been nearly that long. It’s nice to know that he's looking forward to bringing back the character, but the idea that this could be the last time we see Loki might be slightly concerning for fans who might have expected him to be part of Avengers: Infinity War. At this point, Tom Hiddleston clarifies that while there may be plans for Loki beyond Thor 3, nobody has told him that.
I don’t know! Honestly, I don’t know. They haven’t got their ducks in a row yet. They make it up as they go along.
Based on this follow-up info, it seems that when Tom Hiddleston says that Thor: Ragnarok will be his "last time out," what he means is, as far as he is aware, that will be it. It sounds like he would be willing to play Loki again in Avengers: Infinity War, but that as of this point, nobody has spoken to him about doing so. We’re still over two years away from the first part of Infinity War and as the Russo Brothers, who will be directing it, are still putting the finishing touches on Captain America: Civil War , it’s unlikely anybody knows anything official at this point.

We’re hoping we’re not quite done with Loki yet, but if Thor: Ragnarok is the last time we see the trickster god, we’re sure it will be a fitting farewell. One way or another we know we’ll be starting to see some of these characters go away sooner rather than later. Hopefully, the MCU won’t suffer too badly without them.