By the riverside, the morning sun shimmered off the water's surface, casting a reflection like fractured glass. The students of the academy had already gathered, excitedly chattering about today's training session. As Satoru and Eren's silhouettes appeared from a distance, the class quickly settled into formation.
Satoru clapped his hands twice, grabbing their attention.
"Alright, everyone. Today, Sensei has someone special to introduce."
He turned, resting a hand on Eren's shoulder with a friendly smile.
"This is Eren Yeager. Starting today, he'll be temporarily joining our class."
Anko was the first to raise her hand, eyes sparkling with curiosity. "Whoa! A new face! Eren-san, welcome to our class!"
Kotetsu nudged Izumo and whispered, "He gives off a different vibe, huh? Doesn't look like he's from our village."
Eren nodded silently, saying nothing. His deep eyes still carried an exhaustion and sorrow that seemed unshakable. But as he looked at the eager young students surrounding him, a strange, unfamiliar warmth flickered inside him.
Suddenly, Obito dashed forward, grabbing Rin's arm, and excitedly declared,
"Rin, listen! Eren doesn't have any family! His entire village was wiped out in an attack! He's the only survivor! We have to be really nice to him!"
Eren glanced at Obito, his expression unreadable. But somewhere inside, he felt a rare, genuine sincerity radiating from the loudmouthed Uchiha boy.
Satoru cleared his throat, signaling for the class to focus. "Alright, settle down. Today, we continue our balance training."
The class collectively groaned.
"Sensei, more hopping on trees?"
"We've already got the hang of it!"
Satoru smirked mischievously. "Ahh, but today's session will be a little different."
He turned to Eren. "Big bro, today, I'll teach you one of the most fundamental ninja skills—the ability to control the energy within your body to cling to surfaces."
Eren raised a brow. "Cling to surfaces?"
Satoru nodded. "Exactly. Think of it as learning to manipulate your own gravity."
**The Beginning of Something New**
Satoru explained how ninjas channel chakra to the soles of their feet to adhere to surfaces. He carefully demonstrated the key chakra pathways and how to focus energy without letting it burst outward.
Eren closed his eyes and attempted to follow the instructions. However, no matter how hard he tried, he couldn't activate the energy inside him. Unlike chakra, the force within him was wild, untamed, refusing to be controlled.
Satoru crossed his arms, deep in thought. "Looks like your energy isn't the same as chakra. It can't be harnessed through normal methods."
Then, a spark of inspiration struck him. Snapping his fingers, he grinned at Eren.
"Big bro, try thinking about a moment where your life was in danger."
Eren frowned. "Why?"
"It's just a theory," Satoru shrugged. "If your energy truly stems from survival instinct, then the best way to activate it is by making your body believe it's in peril."
Eren remained silent.
Then, he closed his eyes.
He remembered his mother.
Carla Yeager, devoured by a Titan before his very eyes.
He remembered the screams of Eldians, the echoes of their agony slicing through his mind like a thousand blades.
He remembered the burning village, the thundering footsteps of approaching Titans, the sight of those he loved being swallowed whole, one by one.
His mind spiraled into an abyss of darkness.
Suddenly—
**BOOM!**
A surge of chaotic energy erupted from Eren's body.
Dust billowed outward as an intense red heat radiated from his back, fierce like an uncontrollable storm. His skin seemed to smolder, emitting thin wisps of white steam.
His entire body trembled violently.
The class instinctively stepped back, eyes wide in shock.
**Unlocking the Conduits**
Satoru immediately sprang into action, shouting over the roaring energy.
"Big bro, focus! Control it! Guide the flow through your Ren channel, then your Du channel!"
Eren gritted his teeth, his entire being burning red-hot. This overwhelming sensation… he couldn't control it!
But he knew—if he let it run rampant, he would completely lose himself.
Clenching his fists, he forced himself to recall Satoru's teachings.
Inhale.
Direct the energy through his body.
**Ren channel—unlocked.**
**BOOM!**
The wild energy that had been raging like an unchained beast suddenly settled, sinking deep within him. It was still there, but now it was restrained, no longer chaotic but controlled.
Satoru gaped. "Good! Now… the Du channel!"
Eren groaned, his body trembling again.
**Du channel—unlocked.**
**CRACK!**
A rush of heat surged outward, causing the nearby leaves to quiver.
Eren's skin burned a bright crimson, his veins illuminating beneath the surface. He felt as if something was trying to burst free from his core.
And then—
**Snap!**
**BONES.**
From his back, ivory-white bones began to emerge, extending along his arms and spine. They interlocked, forming a thick skeletal armor covering his upper body.
He looked like a warrior forged in the depths of hell.
**A Stunned Silence**
The entire class stood frozen.
No one uttered a word.
Only Eren's ragged breaths filled the air, accompanied by the faint hissing of steam rising from his skin.
Obito's jaw dropped. "W-What… the hell was that?!"
Gai swallowed hard. "He… he just grew bones out of his body?"
Kakashi narrowed his eyes, studying Eren intently.
Anko, however, was absolutely beaming. "WHOA! That was SO COOL!"
Satoru simply stood there, dumbfounded.
He gulped.
"Big bro… I only wanted to teach you how to walk on trees."