No this will not spoil Diamond.
It's just another thing I made cause I had the idea after listening to Impossible Year and reading seven different theories for different fandoms.
Tw for self harm.

Tony Stark hated himself.

Every inch of his arm had been lashed by a knife at some point.

His eyes were always glossy, never really focusing on anything.

Nobody else noticed this.

Sunglasses, so they can't tell where you're looking.

Long sleeves and suits, so they can't see your scars.

A showman's voice, so they can't hear you cry.

And a fake smile, so they can't guess your pain.

That's what it took.

That's what Tony whispered to himself every morning as he got ready to face people.

Those four lines were more deeply etched into him than any of his scars.

Tony thought they were foolproof.

But what's foolproof is not always a hindrance for the wise.

Tony woke up to shouts that morning.

Apparently, Loki had escaped and was feeling quite vengeful.

His plan was to destroy the Earth—unless the Avengers gave into his demand.

He wanted one Avenger to be given up by the others. One Avenger to die at his hand.

And really, when you thought about it as one person or the world, the Avengers had no other choice.

And so Tony woke to a debate about whether he or Bruce would get sacrificed.

"Banner will just Hulk out! He's said it himself, he can't die because of Hulk! Stark doesn't bring much to the team, we can afford to lose him!" Steve screamed. Tony blinked slowly.

Stark doesn't bring much to the team.

We can afford to lose him.

How correct.

"No we can't! We're in his house using his fortune! We literally cannot afford to lose him! I say we go up and battle Loki instead of giving him anyone." Natasha's voice was sharp.

Gold digger, thought Tony, even though he knew it wasn't Natasha's point.

"No! We'd all die!"

"We're really giving him exactly what he wants by fighting! He wants to rip this team apart!"

Tony stepped in between Natasha and Steve.

Steve was right.

Tony was useless, he'd be the first to say it.

"Steve's right, Nat. You can afford to lose me. I left my money and this building and its furniture to Bruce in my will, and the rest of it is being donated. You guys won't have to worry about an impulsive alcoholic or where his money is going anymore. Now, let's get this over with." Tony pretended his hands weren't shaking under his hoodie's long sleeves.

Stark doesn't bring much to the team. We can afford to lose him.

Other times, Tony would have laughed.

He would have joked about how Steve was a gold digger, only after him for his money.

But now, when he knew that was exactly the case?

There was no laughing.

Loki had demanded the entire Avengers come out with the person they were giving up, probably to try and break them apart even more.

So Tony was boarding the jet with his team, for what was his last time, trying not to cry.

There was no way any of them cared about him.

Bruce kept shooting Tony sympathetic glances, but Tony sat perfectly still.

The jet stopped outside of a nondescript office building, Loki's demanded location.

Well.

The office building wasn't just a building—it was the head of the biggest news crew in New York.

And Loki and his army were camped on the lawn.

The jet landed on the grass, the gentle sunlight creating an atmosphere far too friendly for what was going on.

Tony rubbed one of his cuts.

Made the night before, the cut was nowhere near having healed. The skin broke slightly as Tony rubbed on it.

He blinked slowly, pretending he couldn't see the blood staining his hoodie.

Such small things you focus on, when you know the world is about to end for you.

A red bloodstain on a hoodie, for example.

Or a yellow weed-flower in the grass by your window.

Or the shimmer of green as the man who will kill you stands up slowly.

Loki's voice, magically magnified, blasted across the lawn. "Avengers. I presume you are here to fulfill my demands and stop me ruling your earth. As such, you will bring your sacrificial piece up to me, with one escort who is unarmed. The escort will not be harmed by me." Steve stood, grabbing Tony's arm.

"Hurry, Stark, before he gets pissed at us." Steve dragged Tony out of the jet and over to Loki.

Tony didn't mention the fact that Steve's shield counted as a weapon.

Loki didn't seem to care much.

He glanced over Tony, raising one eyebrow.

"You give up your man of iron? Your first fighter? Do you play chess, Mr. Rogers?"

And suddenly, Tony understood.

Breaking the Avengers wasn't the main point. It was more like a happy side effect.

This was a game of chess.

Loki was deliberately giving the Avengers a chance to beat him.

The queen's sacrifice.

A time honored chess strategy.

Loki had assumed Tony was the queen piece.

And he was about to be proven wrong.

Tony shifted his weight.

"I do not play chess," Steve stated.

Loki's face fell, his plan evidently spoiled.

"A pity and a shame, Captain. Well, then this will be exactly as obvious as you thought it would be. Get the rest of your team to watch." Loki turned to Tony. "Come stand beside me. And remove your shirt—I want them to see the blood on your back when I beat you to death."

Tony slowly stepped forward, removing his shirt.

He didn't look back at Steve. There was no point.

Steve could see the scars on his arms, he knew. He could not care.

If it was him or the world, Steve would choose the world every time.

If it was him or someone else on the team, Steve would pick the other every time.

Tony knew he was going to die.

It was strangely peaceful.

The bright sun warmed his back as Loki stood slowly.

Steve's face screamed confusion and morbid curiosity.

Tony knew that Steve was confused as to why Tony's death was supposed to hit him so hard.

And Tony was so busy thinking about that, he didn't realize his death would hit himself so hard.

Loki had summoned a whip from nowhere, a long black instrument with rocks and bits of bone laced into it.

It struck Tony, the rocks ripping his flesh when Loki pulled back.

Tony felt himself fall on the ground, gasping, his face inches from the yellow flower he'd seen from the jet window.

Did Loki see him the way he saw that flower? Something that, even if it was beautiful, needed to die to prove a point, to remove pests?

The whip struck again.

Tears streamed down Tony's face.

He could feel the rivers of blood on his back.

He would probably pass out before much longer.

Loki struck a third time, harsher than before.

Tony squeezed his eyes shut as a hand grabbed the back of his head, pulling him upwards and showing his broken body to the others.

"Fools. You just let me kill your most important piece. You can't have his body, either. Good job."

Tony had been wrong twice.

He wasn't the queen, and it wasn't his sacrifice at all.

Loki had known he was the king.

This was checkmate.

But why had Loki lied about Tony being dead?

Tony didn't have time to think as he was thrown over a shoulder, roughly carried away from the others.

"Don't you make one sound until I say you can, understand?"

Loki's voice was soft now, something almost sweet in his tone.

Tony didn't understand what was happening. He was confused as hell.

So he stayed silent, almost wishing Loki had killed him.

...~...~...

Tony woke to a hand running through his hair.

His first instinct was to jerk away, but he couldn't.

He was tied down.

Slowly he opened his eyes, becoming aware of pains in various places.

His back was probably beyond repair, judging by the fiery feeling.

His wrists had some kind of cloth between them and the ropes holding him.

And, weirdly enough, he was completely clear headed.

He blinked, his vision returning.

Loki was sitting next to him, humming lightly.

The area they were in seemed to be a medbay, from what Tony could see by twisting his head around.

"Stop moving. You'll hurt yourself further. You're bad enough already, and only half of it is my fault." Loki's voice was calm and soothing.

His hand, Tony realized, was the one currently in his hair.

"W-why?" Tony croaked pathetically.

"Why what?" Loki shifted, looking down at Tony.

"Why..." Tony thought about what he was going to ask about. "Why am I not dead?"

Loki threw back his head.

He laughed.

"Have you not seen yourself? If I wanted you dead, you'd be dead. But I don't."

The three short sentences did not help Tony's mental ease at all.

"Why don't you want me dead?"

"Because." Loki's voice was suddenly serious. "I saw the marks on your arm, and I knew it was wrong to kill a warrior like you."

Tony was the one laughing now. He had lost his filter.

"What, my self harm scars?"

"Yes. You're clearly fighting very hard, to have so many. I have been through that gauntlet, and I easily respect another who goes through it."

Tony kept silent.

"Let me think... you volunteered yourself as sacrifice, thinking you were worthless to your team?"

"Yes."

Loki shook his head.

"Nobody is ever worthless. That team, they weren't your real friends. None of them even looked close to crying, except the Hulk."

Tony wanted to point out that Bruce wasn't just the Hulk, but words failed him.

He had always assumed the respect and care he felt for the team was mutual.

But now, it was not.

And they thought he was dead.

"But why go through all this trouble?"

Loki closed his eyes, his hand stopping in Tony's hair.

"I was... deeply impressed by you when we first met. You were confident, snarky... quite excellent at faking ego. I wouldn't think anyone ever saw through you. That admiration, well. I'd never felt like that before. And so my first instinct was to destroy it. That's always been my first instinct—never a really wise one. I thought on it for a long time, and came to realize that that wasn't just ordinary admiration. I... was feeling... attraction."

Loki stopped, looking down at Tony.

"And then when I saw your scars. I could never kill someone who hurt themselves, someone who didn't know they had a place in a realm. I knew that I had to save you. And so I simply faked it, hurt your back enough to seem real, pretended to gloat, and patched you up."

Tony couldn't think.

The trickster god, in love with him.

The man who he'd fought, been thrown out a window by, loved him.

And that man had just freed him from his old life.

More pressingly, Tony's back was really hating his perfectly still position.

"Could you remove the ropes? My back really hurts." Tony whispered.

Loki blinked, then nodded.

He snapped his hands and the ropes disappeared.

"No trying to fight, though."

"None."

Tony tried to sit up.

Pain flared across his back like a third degree burn.

Before he could process it, a cool hand was pressed against his ripped skin.

He could feel his back muscles contracting as skin and bone, tendons and ligaments, all pulled themselves back into their proper positions.

It hurt.

It hurt a lot.

But it felt really good when Loki pulled his hand away and Tony could move.

The pain was gone.

"Are you alright?" Loki's voice was gentle, his hand was in Tony's hair again.

"Yeah, I'm fine now. Where's the army you had going?"

Loki blinked.

"They were an illusion. I dispelled it when I boarded. The only other living things on this ship are junk hoarders working the bridge. Are you sure you're alright?"

Tony tried to regain his normal facade.

"Yeah, yeah, Frosty. I'm fine."

"No. You aren't. Don't use that fake sassy on me."

Loki met Tony's eyes, cupping Tony's face with one hand.

"You are hurting. Your team thinks you are dead. You just found out your enemy and capturer—that's me—is in love with you. You've killed the skin on your arms. Don't pretend to be fine."

Tony was shaken by Loki's care.

Never had someone seen through his sharp attitude.

And now the god who was in love with him was cradling his face and saying he'd seen straight through it.

It was too much to take.

Tony started crying, the sobs racking his body.

Loki's arms swept around him, holding him close.

"You poor dear. Can you promise me one thing?"

"I suppose..."

Tony could tell he was getting snot and tears on Loki's fancy clothes, but the god didn't seem to care.

The two men held each other for a long time before Loki spoke again.

"You have to promise to never hurt yourself like that again. Whenever you feel like cutting yourself, you come to me, alright?"

"Okay."

"We can start ourselves a new life here, just us. I'll take care of you, make sure you're always mentally healthy. You will be safe, and we'll be happy... you do feel at least some attraction towards me, right?" Loki's voice was suddenly worried.

"Duh. You're like, the sexiest god ever." Tony chuckled into Loki's shoulder.

"Of course I am. Now, let's get you something to eat and then some rest."

Loki stood up, scooping up Tony bridal style.

Tony wrapped his arms around the god's neck, hiding his face in Loki's chest.

Loki smiled down at the man in his arms, quickly kissing his forehead.

Tony would never admit how much he blushed.