Casting somehow managed to temporarily de-age Hiddleston and dye his hair black. That’s all there is to it.
And this scene. Unnngh my heart. All aboard the feels train, people.
That look he gives Odin there at the end, after Odin tells the boys that both of them were born to be kings but only one can take the throne. It just. Does things to me. Like rip my heart open, basically. That expression in the last gif is one of thoughtfulness, then worry, then sad resignation because he knows, even at such a young age, before his entire world’s been shot to hel(l), that it’s never been a contest. Thor is older. He is the golden child, the good child, the favored one. Of course he’s going to be king. When told the story of the frost giants, Loki’s instinctual response was one of fear, but also curiosity, because he is an intensely curious and intelligent person. Thor’s immediate response, meanwhile, wasn’t that same morbid interest or anxiety, but rather a gut instinct to attack. “When I’m king,” he says, because there’s no doubt in his mind about that, either, he’s going to “hunt them down and slay them all.” No questions asked.
Let’s look a little deeper at that scene. Imagine you’re a young boy — which might be a century or more at the rate your people age, but you’re still very young, still a child. You’ve grown up hearing these fantastic stories about your father’s heroic deeds and this immensely important battle with the frost giants. You look up to him, idolize him. You ask if the frost giants still live, partly to gauge Odin’s success in the battle, partly out of simple curiosity because you have to know everything about everything, and partly because of a childish need to confirm there aren’t really monsters hiding under your bed at night. But your father doesn’t get a chance to answer. Your big brother, your best friend, jumps in and promises to “slay them all,” just as he’s always done after your busy imagination conjured up visions of the monsters at bedtime and you found yourself too scared to sleep. He has always kept the monsters at bay, and he swears to do it in a literal sense when he’s older. When he’s king. And you accept that.
Now flash forward several years/centuries. What you always thought to be a foregone conclusion — Thor will be king — is in jeopardy. Everything has gone upside down. Your mother always warned you that your passion for tricks was going to blow up in your face someday, but you didn’t listen. Your “bit of fun” in crashing Thor’s coronation set off a chain of events that will quickly prove to be your total undoing. It will unravel everything you’ve always believed like a worn thin thread frayed at the ends. You knew the guards would stop the frost giants from stealing the casket. Perhaps you didn’t anticipate the guards giving their lives, and you feel badly for that, but you knew the giants would be stopped. Thor’s arrogance would be shaken by the fact he had a near disaster on his hands the second he became king and you could laugh at watching him get taken down a notch or two, but that’s the extent of things.
Except it’s not. It’s so not, because you’ve underestimated Thor’s resolve and his arrogance. He suggests a trip to Jotenheim. A world of ice and darkness, the abyss you were taught to fear as a child. And now your brave but foolish brother wants to march into that pit and make good on the promise that still rings in your ears, to slay all the frost giants. It is a fool’s quest, but you agree to accompany him anyway because as much as it terrifies you, your curiosity demands that you get a closer look at this place. There are secrets to be had here, and you intend to uncover them.
So you arrive in the darkness and you are puzzled by the fact that you do not feel the sting of the ice and snow nor the bitterness of the freezing wind as severely as do your friends, who are all more heavily clothed. You walk in silence, the noise broken only by crackling ice and howling wind, and then you see it. Him. No, it, the king of the frost giants, the beast you have feared your entire life.
There is a traitor in the house of Odin, and the monster looks your way. You struggle to hold his gaze.
You pull Thor back from the brink, because this has gone much farther than you wanted. But Thor will not be taunted like a child, and so the first skirmish of the new war erupts. You are not a warrior. You are a planner, a thinker, a “carnival magician,” Volstag once scornfully called you, but you stand your ground and fight regardless. The Warriors Three have always derided you for being a “coward” because you use your magic to fight at a distance, so you try to prove them wrong by attacking a giant by hand. It grabs your arm before your blow hits, and Volstag’s warning replays in your head: “Don’t let them touch you.” You expect the pain and bite your tongue to keep from giving the monster the pleasure of hearing you scream; it got enough of that when you were a child and woke from nightmares of the beasts. But the pain never comes. You stare in shock, in horror at your arm. You look up into the face of the beast and there is a spark of recognition. I know you, his eyes say, and you know in your heart that it’s true.
The connection ends, the spell breaks. You’re not sure you’re thankful.
You see a friend—Thor’s friend, really, but Fandral has at least always been kinder to you than the others—impaled on the ice and you feel desperate, scream for Thor to pull back because you must leave to help your fallen comrade. Odin rides in to your rescue, both to your relief and humiliation, and all of you return to Asgard. You return in body, but some part of you that you can’t identify remains in the land of the frost giants, dead and frozen.
Your mischievous nature has not only cost Thor his crown, but gotten him banished to another realm and pushed Asgard to the brink of war. This isn’t what you wanted.
Later, when you work up the nerve to confront your father about your peculiar experience in Jotenheim, when you learn the damning truth, all you can think about is Thor, and isn’t that funny? Even now, even when he’s been banished to an entirely different world, even now you can’t help but think of him. He’s always been your protector. Your brother. Your friend. Misguided and frustratingly self-assured, but you love him all the same. You hear the truth from your father — not your father, your real father showed you the truth and looked you in the eye and you knew but still couldn’t accept it — and all you can think of is that day in the treasure vault. “Do the frost giants still live?” you asked, and Thor didn’t hesitate to announce his plans to kill all of them.
He was standing right next to one the entire time.
You have feared yourself your entire life without even realizing it.
There is no monster under the bed, but in it, sleeping inside you, waiting.
“You were both born to be kings.”