Now let's introduce kid Eren and his friends (Mikasa and Armin) into Conan's school and explore their interactions with the Detective Boys, particularly when Levi is in charge of gym class:

Title: Clash of the Crews

It was another lively day at Teitan Elementary School. Levi was standing in the middle of the gym, arms crossed, his sharp eyes scanning the students like a hawk as they prepared for their PE lesson. His firm voice cut through the chatter like a blade.

"Get moving! You're wasting time," Levi barked, his usual impatience on full display.

Conan and the Detective Boys were there, eager to dodgeball their way to glory. Across the court stood Eren, Mikasa, and Armin, recent transfers to the school. They were quieter but no less determined, their expressions serious as they discussed strategy.

"This is a team sport," Eren muttered, his brow furrowed. "We have to work together."

Mikasa, ever protective, nodded. "Just stay close. I'll make sure you don't get hit."

Armin, clutching the ball nervously, glanced at the opposing team. "I don't think it's going to be that easy. Look at Conan—he's analyzing everything!"

Conan stood on the other side, adjusting his glasses with a confident smirk. "They look serious, but we've got teamwork down."

Ayumi cheered, "Let's show them what the Detective Boys can do!"

The Battle Begins

The whistle blew, and chaos erupted. Levi watched from the sidelines, arms folded, as the two teams went head-to-head in a dodgeball match that felt more like a battlefield.

Eren, driven by his fiery determination, launched himself into the fray, throwing the ball with impressive force. Conan dodged it with ease, his quick reflexes saving him from elimination. Mikasa, always precise, deflected an incoming ball aimed at Eren, earning murmurs of admiration from the Detective Boys.

"Whoa! She's amazing!" Ayumi exclaimed.

"Not bad," Mitsuhiko added, his eyes wide.

Meanwhile, Armin found himself cornered by Genta, who was charging toward him like a tank. Panicked, Armin called out to Eren. "Help!"

Eren dove forward, grabbing the ball just in time to shield Armin. "Stay focused, Armin! We can't let them win!"

Levi smirked faintly, watching the chaos unfold. "Amateurs," he muttered, though there was a flicker of approval in his eyes as he watched Mikasa's sharp movements.

Levi Gets Involved

As the match continued, tensions rose, and both sides began to push their limits. Conan, spotting an opening, lobbed the ball straight toward Eren, but Mikasa intervened, catching it mid-air.

"Nice catch," Levi muttered from the sidelines, his tone laced with respect. Mikasa didn't react—she was too focused on protecting Eren.

Eren, clearly fired up, launched the ball with all his might, aiming directly at Conan. Conan dodged at the last second, his glasses slipping slightly but his smile never faltering. "Close one!"

Seeing the energy escalate, Levi decided to step in. Grabbing the whistle, he stormed onto the court. "Alright, enough playing around. If you're going to fight, do it properly."

The students froze, staring at Levi with wide eyes. "What do you mean, Levi-sensei?" Ayumi asked cautiously.

Levi smirked. "Two teams. Me on one, Erwin on the other. Let's see what you kids are really made of."

The Adults Join

Erwin, who had been observing quietly, stepped forward with his usual composed smile. "I suppose this is inevitable. Let's keep it friendly, Levi."

"Tch. Friendly's boring," Levi replied, grabbing a ball and spinning it in his hand. "Let's go."

The match became a whirlwind of action as Erwin led his team with strategic precision, guiding Conan and the Detective Boys in coordinated attacks. Levi, on the other hand, relied on raw speed and ferocity, inspiring Eren, Mikasa, and Armin to give their all.

"Come on, Eren!" Levi shouted as Eren narrowly dodged a ball. "Is that all you've got?"

Eren gritted his teeth, throwing the ball with renewed force. "I won't give up!"

The gym was filled with shouts and laughter as both sides fought tooth and nail, the match ending in a chaotic tie.

Friendships Blossom

After the match, both groups of kids found themselves chatting excitedly about their favorite moments. Eren and Conan bonded over their shared determination, while Mikasa and Haibara exchanged subtle nods of mutual respect. Armin, still slightly frazzled, found comfort in Mitsuhiko and Ayumi's cheerful encouragement.

Levi watched them from the sidelines, sipping his black tea with a faint smile. Erwin joined him, his expression thoughtful. "You seem to have quite an effect on them, Levi."

Levi snorted. "They're loud, but they've got guts. Maybe they're not so bad."

Erwin chuckled. "It's not every day you see two worlds collide so seamlessly."