a/n: so I was gonna write something happy/fluffy for the next one but then I had a dream about these boys last night:

It was supposed to be Rin who messed things up.

Rin was the fuck-up, the one who leaped before he looked, the one who spoke without a filter. Yukio, on the other hand, never miscalculated. Everything action, every word, every shot was precise, leaving no room for inaccuracies. No room for mistakes. It was perfection or it was nothing at all.

Sometime during this mission, their roles had switched.

Rin watched with bulging, terrified eyes as the bullet from his brother's pistol missed its intended target by a hair. Watched with rapidly increasing horror as a slimy arm snaked around Yukio's torso. Watched as both guns were knocked out of his hands, as Yukio was thrown into the air like a rag-doll, too stunned to make a sound. Watched as he came plummeting back down at a nauseatingly fast speed.

"No," he whispered, feet already moving, gaining momentum with each passing second. "No, no, no, no—"

"Rin! Don't!"

Faster.

If Rin fell at that speed, he'd survive. His fight with Amaimon had proved that. But Yukio was human! A human with bones like glass and paper skin, easily torn, easily crushed.

"You're going to get hit, too!"

Faster.

Sword already drawn, Rin threw himself into the air, flames and all, fueled by the gut-wrenching, sickening realization that if his brother hit the ground Rin would lose the only person he had left.

"Okumura!"

Faster.

He hurled blue flames outward, barely pausing as his target became engulfed, screeching and hissing.

"YUKI-CHAN!"

Faster.

Rin caught him just in time, twisting his body so he could land properly, and as his feet collided with the earth his heart was racing, thumping wildly within the confines of his ribcage like it was trying to break free.

"Try to kill my brother again," he growled, looking at the smoldering remains of the demon with feral eyes. "I fucking dare you."

He had Yukio in an iron grip, practically seething with rage. An image of a mangled, bloody body flashed through his mind and it wouldn't leave. He'd already lost his old man. He couldn't lose his brother.

The demon was dead and fading, but the tension didn't leave Rin's body until it was gone completely.

"Nii-san," Yukio murmured when Rin still didn't release him, his tone calm, but the tinge of hysteria in his eyes betraying him. Yukio had been scared, too, no matter how much he tried to hide it. "It's... it's ok. I'm fine."

Shiemi and Shura came running over to them, followed by the rest of the class. Shiemi asked fretfully, "Yuki-chan? Rin? Are you both alright?"

"We're fine," Yukio repeated softly. Woodenly. "I... I miscalculated."

That's my job, Rin thought as he mechanically sheathed his sword, trying not to choke. The flames disappeared but the anger and fear lingered like a terrible aftertaste. Out loud: "You should be more careful."

The irony in that statement was almost comical, he realized. Because Rin was the one who so often danced with death, the one who got scolded. Not Yukio. Never Yukio.

A whisper of sad understanding flickered through his brother's eyes. He didn't roll his eyes. Didn't scoff. Didn't call Rin out for his hypocrisy. Just said, "I will."

Rin nodded. Pretended he wasn't shaking.