Shingeki no Yaiba (Demon Slayer x Attack on Titan crossover)

ODM machines

"Listen up, cadets!" Shadis cried, marching up and down the rows of children, glaring. "Today you will begin training on the Omni Directional Mobility gear, as the grown ups like to call it, ODM gear, and as I like to call it, something to get rid of a lot of you weak ass babies!" He raised a finger to point at one of the five machines that had been set up during the night, each constructed of four wood poles meeting at the top, and complicated looking wires and belts that somehow formed a sort of harness.

I'll be okay. Urokodaki had one of these and he trained me on it, so I know what I'm doing. Tanjiro took a deep breath. I'll be okay.

"Cadets! Line up and fail!"

Tanjiro took Nezuko's hand and the two of them got into line at the first of the five machines. They moved slowly, as each cadet had to be set up and then try, and usually fail, to balance. As more and more cadets ran off trying not to cry, it became harder and harder for Tanjiro to keep calm.

Finally, at the machine next to his, it was Eren's turn. The boy sauntered up to the machine, putting his arms out as the assistant clipped him up. He nodded to the boy and he shrugged, starting to wind up the wires so Eren would float. But the moment Eren's feet left the ground, he yelled in horror and flipped upside down, waving his once steady hands around in panic.

"After all that big talk and that's all he does?"
"What a disgrace."

"Get off the machine. It's my turn!"

"God, what if I do that?"

"How embarrassing!"

"Eren!"

Mikasa scrambled out of her own machine where she had been perfectly balancing and ran to Eren's side, trying to reassure him with, "You can do it, Eren! Just try to get upright again!"

Eren certainty was trying, but it wasn't working in the slightest. He kicked his feet, waving his arms and straining his body but no matter what he did, he was stuck hanging upside down.

Poor guy. I wish I could help him. Tanjiro sighed, then grunted as a rough hand pulled his back. He stumbled forward, starting to look back in annoyance but realized why the man had done it. It was his turn.

Nezuko patted him on the head, nodding, and he smiled as reassuringly as he could.

Okay. I've got this.

He walked carefully up the machine, putting his arms out as he was clipped up.

"You ready?" the assistant asked, barely waiting for him to nod before he walked to the crank and started to turn it.

Tanjiro put his hands out, palms facing down and steadied his back, flexing his feet. But something was off this time. It didn't feel like it had when he had done it on Urokodaki's mountain, floating easily off the ground and keeping his position in the air, the belt pulling where Tanjiro could reposition himself to keep balance. No, this time something was—

"Wait..." he tried, but his feet were already lifting of the ground, and before he knew it he was swinging upside down, facing Eren. The boy stared at him, still in shock. He'd messed up. Somehow, he'd failed at what he hadn't even been worrying about! But here he was, upside down.

How? That was the first question that calmed his scattered thoughts. He knew he'd memorized exactly how to balance on these machines at his teacher's mountain, so how had he failed?

No, what if they'd changed it up? What if they'd updated the gear since Urokodaki's time?

"Tanjiro Kamado!" Shadis stalked up to him, ignoring Eren save for a look of contempt sent his way. "I see that someone tried to get ahead of the others and practiced on their own. But you messed up! The way you're balancing was deemed unsafe twenty years ago, and the belts have been changed. It seems all your work was useless, cadet!"

Tanjiro's eyes widened in horror. All that time had been useless? All the effort Urokodaki had put into him had been for nothing? No, he wouldn't let that be true. He had to live up to his master's wishes and demands of him!

"Let me try again, sir!" he demanded of the commander. "Please! I know I can get it!"

"Get off the machine, cadet."

"Sir!"

A sudden pain to his chest made Tanjiro gasp for breath. The commander's boot hit him again and he swung backwards, falling to the ground as the assistant released the crank and loosened the wires.

"I said get off the machine," the commander growled, raising his boot to kick again, but before he could a shadow raised behind him and Nezuko swung her fist towards him with all her titanous might.

"Nezuko! Stop!"

The girl froze and the commander turned to see her first inches from his bald head.

"Is there a problem, cadet?" he hissed, not shaken in the slightest. Nezuko glanced towards Tanjiro, her expression softening, and her eyes whispering, are you okay?

Tanjiro nodded quickly and Nezuko did the same to the commander.

"Good. Because you're up next." He turned a perfect 90 degrees and stomped off to yell at Eren for being weak and useless. Nezuko hurried over to help Tanjiro up and out of his tangle of wires, grunting worriedly.

"I'm okay, Nezuko. I'm okay." He winced as his wounded chest took the weight of his body but didn't let the pain show on his face. As the eldest son, he couldn't. Not in front of Nezuko.

"You. With the weird muzzle. It's your turn," the assistant snapped, shoving them apart. "You messed up, kid. Now..." he lowered his voice and whispered kindly, "get back in line if you want to try again. I'll wait."

Tanjiro stared at him, then smiled. "Thank you so much."

He nodded, then raised his voice again and ordered, "get in the harness, little lady. And good luck."

Nezuko nodded to Tanjiro, then walked up to the harness, standing perfectly still as she was clipped up. Tanjiro paused his walk back to the end of the line to watch her nervously. But there was no need to worry, as Nezuko was lifted on the ground and stayed upright, barely having to strain to stay that way. She looked towards Tanjiro for affirmation and he smiled, mouthing, great job! She grinned.