The arrow, obviously, did not come to be lodged in Loki's shoulder by accident, or by its own design12. While many inanimate objects in this story possess a surprising amount of anima, this particular arrow was not one of them.
In fact, the arrow belonged to a man named Clint "Hawkeye" Barton, who had decided that somewhere in Loki's meaty bits would be a lovely place to keep an arrow. Really, the arrow was just along for the ride.
And how Clint came to be perched on a roof in suburbia next to a large, blond man with linebacker shoulders and a scarlet cape, was a little ditty that went something like this:
Clint was in the middle of teaching Thor how to play pool, or rather, teaching him how to play it so badly that Clint would never have to buy himself another drink. He'd just gotten to the part about making sure to hit the cue ball really, really hard so that it would know you meant business when Agent Romanoff showed up, wielding a little manilla folder. And while Clint was normally in favor of seeing Agent Romanoff, the little manilla folder said that it might be time to do some work, and he really just needed a goddamn vacation already13.
"We've got a power surge," she said without preamble, holding out the folder.
"Sounds like a personal problem." Clint gave her one of those grins that plainly said, 'You can't make me.'
She waggled the folder at him. "There's a parolee living in that part of the grid. A giant robot guy." She smiled right back at him, a level expression that said just as clearly, 'I'd be happy to, but you won't like the results.'
Clint groaned. "Oh come on. Don't these jerks have something better to do with their time than watch anime?"
"Obviously they do. That would be building giant robots in a valiant effort to keep people like us employed."
"Other than those two things, I mean. You'd think with all the por--"
"--and because it's a giant robot situation, I'm handing this over to Thor." Which she did. He took the folder without complaint. "Have fun, boys. It should be just a short hop for you." She turned and walked away, a jaunty swing in her step that affected Clint's language centers to the extent that Thor had to repeat himself four times before it sounded anything like English.
"We'd best leave quickly," Thor said. "Quickly. Quickly, Clint. This is not very quick, Clint."
Clint waved Thor off with one hand, still staring at the doorway Agent Romanoff had exited through. "You can go ahead without me, if you're in such a hurry." For a split second, he considered following her, but it hadn't been so long since he'd been put in an arm lock that he was eager to try another. There was a reason they called her Black Widow, and it wasn't because she came with a red hourglass as a warning label.
"No, we're to go together," Thor said, as if trying to explain a tricky concept to a child. "I break the robot with Mjolnir. You shoot the inventor. It's our plan."
As plans went for Thor, it was surprisingly sophisticated. Clint sighed. "Fine. I'll grab my gear. See you at the helipad in three."
Except when he got to the helipad, there was no helicopter. Thor stood where the helicopter should have been, wearing his ridiculous little winged helmet and swinging Mjolnir idly in lazy circles. And maybe it was Clint's imaginations, but he could have sworn he heard the guy humming 'Ride of the Valkyries.'
"No way in hell," Clint said.
"It's the fastest way to get there," Thor pointed out.
"Do I look like fucking Lois Lane to you?"
Thor frowned. "I've seen pictures, and she is a lovely and refined lady. So no, you are far too ugly, my friend. Come." He walked over to Clint, and despite his protests, wrapped one beefy arm securely around the man's waist. "If you're afraid that this will somehow impugn your manhood, you have my word of honor that I will tell no one if you scream."
"If you fly upside-down, so help me..."
"For your convenience, this god has been equipped with an air sickness bag."
"You've got to be kidding!"
"I am. I'm glad that you noticed." And then Thor took off.
Clint wasn't a guy that was afraid of heights or a little speed. He couldn't be, not in his line of work. He just didn't necessarily want to go squeeling with adrenalin-induced glee when he was having to cling to a Norse god like a girl on a pulp fiction novel cover14.
After five minutes of flight, they stopped on top of a water tower so Clint could check the maps from Agent Romanoff. At which time he had to point out to Thor that, for fuck's sake, the sun rises in the east on the planet Earth.
Ten minutes after that, they set lightly down on the roof of a split level that looked like every other split level, except it was across the street from Daniel Sorres' house. Clint was all business then, bow ready, arrow knocked, and staring in the front windows as he waited to see a sign of life. Thor tried to poke his head up over the peak of the roof, and Clint shoved him back down when the sunlight flared off his helmet. "You are about as subtle as a kick in the ass," he muttered. "Okay, there's no car. Maybe you should go around the back..."
And then someone came into view.
Part of the reason Clint was the best marksman the world had ever known was that he could recognize a face in a split second, quantify if the face belonged to someone he wanted to shoot or not, and then decide where to stick the arrow without having to actually consciously think about it. It was just a little switch in his brain that went off, and only later did he take the time to assess why exactly he'd fired.
So his eyes saw dark hair, thin hands, a foxy face, and then the arrow was let loose.
Loki went down like a sack of bricks.
"What the-- was that my BROTHER?" Thor shouted, grabbing Clint by the arm and yanking him around.
Clint took a moment to sort through all the information his brain threw at him, then let a slow grin creep over his face. "Yeah, I guess it was."
"You shot my brother!"
"Hey, he's dodged every other arrow I've tried to put through him," Clint said. "So really, it's his fault."
But Thor was already across the street and bolting through the broken window.
12 – Though if anyone did bother to ask the arrow what it thought in the brief seconds between it being catapulted from a bow and cutting through Loki's clavicle, its response would have been something like "FUCK YEAH!" had it been capable of even so rudimentary a thought.
13 – Except for a five day stretch in 1986, there has actually not been a moment in recorded history when Clint Barton didn't need a goddamn vacation.
14 – Little known fact: Clint had once, on a drunken dare, dressed up in something red, slinky, and straight off a pulp novel cover. The fact that he still hadn't figured out where Coulson kept the pictures of that evening was the reason that whenever some asshole microwaved fish without covering it, Clint was the one that got stuck cleaning up the mess15.
15 – Little known fact: Agent Coulson's favorite quick meal was microwaved fish filet, a hamburger bun, and the salty tears of Clint Barton.