Flesh and steel clashed.

With a noise that felt like the world breaking apart, a powerful shockwave surged in all directions.

The visible shockwave shattered already crumbling buildings as it spread out. Despite being merely flesh, a mass of protein and fat, Galrm blocked the steel punch with a smirk, then swung back at the incoming fist.

"Show me everything you’ve got!"

Responding to Galrm’s taunt, the Steel Titan unleashed its arsenal of unused war weapons without restraint. An 800mm cannon, capable of obliterating a tank in a single shot, fired with a thunderous roar.

The cannon, impossibly large for a typical gun, fired a shell several times Galrm’s size, which hurtled forward, ready to destroy anything in its path.

The shell fired with speed too quick for a normal creature to react. But Galrm wasn’t just any creature.

He was the pinnacle of biological evolution, enhanced by Leviathan’s genetic material and having evolved in the direction he desired, making him the most powerful being on Earth.

‘It’s massive… I’ve never seen anything like this, even in my prime!’

Catching sight of the shell, Galrm reached out and caught it mid-flight. As his hand brushed over the shell, guiding it away, it ricocheted off into the distance.

The effort of deflecting a shell many times his size and weight came at a high price. Blood vessels and tendons in Galrm’s right arm burst under the strain, and blood began to ooze from his forearm.

Looking down at his trembling arm, Galrm grinned.

"Is that all you’ve got? If you’re going to destroy a city, you’ll need more than this."

[Enemy unharmed.]

Watching the taunting Galrm, the Steel Titan calmly raised both hands. Dozens of gun barrels emerged all over the Titan’s body.

The ominous barrels, each as large-caliber as the earlier cannon, all aimed at Galrm.

[Firing all rounds.]

With a deafening blast that could signal the end of the world, the Steel Titan launched dozens of shells at Galrm.

Galrm took a deep breath, then raised his hands and began deflecting the shells.

Some exploded prematurely, engulfing him in fireballs, yet Galrm endured it all.

"Haha! This is fun—so much fun!"

Now it was his turn. As Galrm prepared to advance, his body suddenly froze.

After pushing his body beyond its limits, it had finally given out.

Galrm realized instinctively that this was the side effect the scientist had warned him about. He’d forced himself to perform actions that were impossible with only one genetic material, so it was no surprise his body was failing him.

‘Damn it, is this the end…?’

As he stared blankly at the Steel Titan, he heard a familiar song coming from somewhere.

A song that was familiar to him, the kind he’d often hear back in E City when he had nothing else to do.

—Listen to my song!

With electric guitar, bass, and drums blasting through the battlefield, even the Steel Titan momentarily froze at the sound.

As the giant robot halted, Levithan dashed over, grabbing Galrm by the waist and sprinting away.

"You idiot! I told you this wouldn’t work alone!"

"…Levi, than."

"Ugh! Geez! Eighth said he’s coming! We’re retreating!"

"The scientist, here?"

"Yeah!"

It didn’t make sense. How could the scientist possibly be here? Galrm looked up, and then he understood.

In the distance, something was flying toward them, leaving a contrail in its wake. It was far too large and moving far too fast to be a mere plane or fighter jet…

[Enemy detected.]

The Steel Titan aimed its cannons skyward as its radar detected the approaching object. Before it could fire, however, the incoming object accelerated even faster, delivering a kick to the Steel Titan’s face.

[Falcon Kick!]

The immense weight of the Titan recoiled from the impact, throwing it off balance. As it stumbled, a second robot landed on the ground and aimed a punch at the Steel Titan.

"Greetings, big brother."

[…You.]

"I am the ST Series No. 2, Steel Falcon."

Falcon bowed lightly.

"I am your little sister."

With those words, something within the Steel Titan shattered.

"Ugh… ahhh—!"

Acceleration pulled at his body, and for a moment, Steel Falcon felt the blood rush to one side. The next moment, the robot landed on the ground, facing the Steel Titan.

I turned to Steelstone, who was gripping the controls tightly, and shouted.

"Steelstone! We’re here! Pull yourself together!"

"Ugh… huh… Already?"

"Yes! It’s your turn now!"

Unlike the fully automated Steel Titan, the Steel Falcon was manually operated. This was due to Steelstone’s insistence that he couldn’t entrust disciplining one child entirely to another.

I had agreed to this whim, even though, in retrospect, it was a little reckless…

‘I mean, how could you resist piloting a robot?’

In any case, I didn’t actually expect Steelstone to beat Titan by piloting Falcon. Even if he moved the controls, Falcon wouldn’t follow him completely. Like an assist mode for beginners in a fighting game, Falcon’s AI would find the best solution independently.

The controls were about sharing responsibility—the responsibility of creating a monster like the Steel Titan. The responsibility of punishing it with his own hands.

The responsibility of a parent.

[Sis…?]

"Yes, big brother!"

With that, Steel Falcon swung its leg. Unlike the hulking Titan, Falcon’s body was agile. Its kick struck the Titan’s side, leaving a deep dent.

Falcon smiled, pleased with the effectiveness of its attack, then prepared to launch another strike.

"…Falcon, I’m counting on you."

"Yes, father."

"Father… Wait, does that mean…?"

"Father is with me. Big brother never had the chance."

[We have no parents. Only masters and… pilots.]

Steel Titan’s eyes flashed as it rejected Falcon’s words.

[Just pilots.]

In the next moment, every weapon on Steel Titan’s body became visible. Built to wage war single-handedly against the entire world, Titan unleashed its arsenal of bombs and missiles.

It fired all remaining shells in a frontal assault that even Falcon would struggle to survive.

"Falcon! Form change!"

"Yes, father!"

Falcon responded by shifting form. Its body transformed like a fighter jet, accelerating rapidly and evading the barrage of missiles and shells.

Unlike the war machine Titan, Falcon carried only one weapon—speed. It had sacrificed everything else for that one purpose.

[Falcon Kiiiick!]

Falcon, darting around Titan’s head, exploited a gap in Titan’s defenses and plunged downward.

Like a hawk hunting, Falcon continued to soar and dive at Titan’s head.

But Titan’s ability to devastate W City wasn’t mere luck. Adapting swiftly to Falcon’s movements, Titan grabbed its leg and threw it.

[Aaah!]

Falcon screamed as it crashed into the rubble. It quickly transformed and escaped the impact zone just before the spot was bombarded with shells.

Seeing Titan’s distant barrage, Falcon cried out in frustration.

"Father! I don’t have any ranged attacks!"

"…Sorry."

"Always favoring big brother! It’s so unfair!"

Complaining, Falcon once again evaded the barrage with acrobatic maneuvers and rushed over to grab Titan’s legs.

At first, it wasn’t clear what Falcon was doing, but then its engines began to overheat to the point of melting.

"Grr… aaaah!"

"What are you…"

"Die already! Damn big brother!"

Falcon’s turbo engines roared, and it lifted the massive Titan off the ground, taking flight.

Rising high, Falcon flipped Titan and drove it straight down, slamming it into the ground.

[Falcon Driver!]

With a thunderous boom and a tremor that shook the earth, Titan was left buried head-first, wriggling helplessly.

Falcon sighed and spoke.

"Now, do your thing, father."

"…Ah, yes."

Steelstone, watching the sibling brawl, shivered slightly.

I couldn’t blame him. Even from where I stood, Falcon’s deadly intent toward her brother was enough to send chills down my spine.