Charlie was unaware that Aishia and Kei were intensely discussing him as their topic. Right now, he was flying in the Troposphere—or more precisely, at its upper boundary, about 12 km above the ground.
The question of why he chose the Troposphere wasn't without solid reasoning.
Why the Troposphere?
There were several practical considerations: the air at this altitude was still dense enough to generate lift, there was less turbulence and extreme weather compared to near the surface, and it allowed him to avoid most storm clouds that formed at lower altitudes.
In fact, ordinary commercial airplanes flew in this layer, proving the Troposphere was a relatively safe zone for flight.
Charlie hovered above the cloud surface, enjoying the view of a cloudless blue sky that had become rare and unseen for the past year in this world.
Thanks to the blessing of his Six Eyes, he could clearly see the International Space Station floating silently, along with various remnants of human space exploration like rocket boosters, dead satellites, and other debris still orbiting Earth.
"Even the astronauts up there didn't survive… Without resupply shipments from Earth and with limited resources, it was only a matter of time before they starved to death."
Detecting no signs of life at the International Space Station, Charlie sighed sadly.
However, he didn't let himself drown in sorrow for too long. He quickly shifted his thoughts to his main purpose for being at this altitude.
"Alright, let's see how much my speed has improved after reaching Level 6."
Not lingering in sadness, Charlie turned his attention to the speed-measuring device he had made in his spare time.
"39,520 km/h… This is the Second Cosmic Velocity!"
He exclaimed in shock at the number displayed on the device in his hand. Charlie even rubbed his eyes, thinking he had misread it.
"This is real! My speed has truly reached the Second Cosmic Velocity… It's hard to believe a human can fly this fast with just a body of flesh and blood."
"Before, my flying speed was only around Mach 12. Just by leveling up once, my speed skyrocketed significantly to touch Mach 32!"
The Second Cosmic Velocity is the minimum speed required for an object to escape Earth's gravity without additional thrust after reaching that speed9.
"That means I'm now faster than Koro-sensei."
Charlie couldn't help but recall the yellow octopus teacher who taught the meaning of life under the guise of assassination to the worst middle school class.
"With my Second Cosmic Velocity, I could circle the Earth in just one hour… Hm? Something feels off. If I'm not mistaken, Koro-sensei's speed was only Mach 20, but why could he circle the Earth in less than an hour when I'm superior in speed?"
Charlie pondered this issue seriously. He wanted to understand the difference between them.
Soon after, he came up with a logical speculation.
"His unique physical factors and techniques. Koro-sensei pierced the air with perfect efficiency, his body could change shape for aerodynamics, and he took sub-orbital paths. Plus, he was the Strongest Assassin in the world, so his perception was extremely high."
"All those factors allowed Koro-sensei to maximize his speed potential. Even though I'm faster than him, my control is worse. After all, I just obtained the Second Cosmic Velocity. If I train it, circling the Earth in less than an hour isn't impossible."
Charlie nodded at his own conclusion. This achievement was indeed extraordinary, but there was still room for improvement. He now realized that raw speed was just one part of the equation—perfect control and efficiency were the keys to fully utilizing it.
"I'm curious if I can survive in space without any protection."
Looking up, outer space seemed so close, as if he could just reach out and touch it.
"Let's do it!"
"After trying my hardest, giving up at the last step would fill me with regret. Even if I fail, at least I'll know I tried."
*WHOOSH!*
No longer hesitating, Charlie shot forward at full speed, piercing through Earth's atmospheric layers. Stratosphere, Mesosphere, Thermosphere, Ionosphere, Exosphere—all layers passed in seconds.
Finally, he successfully left Earth!
With agile maneuvers avoiding flying space debris, Charlie landed steadily on the surface of the International Space Station.
He opened his mouth, but no sound came out. There was no air in space, so sound couldn't propagate.
(This is incredible…)
His gaze fixed on Earth below. The beautiful blue planet hung in eternal darkness, like a precious gem nestled in a black velvet expanse. Unfortunately, he couldn't see a single continent due to the volcanic clouds covering it.
(How small we are… all of human civilization, all our history, all our achievements and failures—everything exists on this small blue ball.)
He looked further into the boundless darkness adorned with countless stars. Each point of light was its own sun, possibly with worlds orbiting them.
(The universe is so vast… and we are just a speck of dust in this infinite cosmos. All our problems, all our conflicts—they all feel so trivial from here.)
Fortunately, Charlie didn't suffer from astrophobia—fear of space and celestial objects. Instead, he felt awe and connected to something greater than himself.
(But precisely because we are small, every act of kindness, every effort to be better—that's what makes us meaningful. Even as a speck of dust, we can shine brightly in the darkness.)
He stood there for a few moments, mesmerized by the grandeur of a view rarely seen directly by humans. This experience gave him a new perspective—on life, on his struggles, on the meaning of being human in a vast universe.
(I don't feel any discomfort. It seems space radiation has no effect on me. The question is, can all Level 6 adventurers survive in space, or am I a special case?)
Without a valid comparison sample, he could only guess.
(With my current power level, holding my breath for six hours isn't hard, but not breathing at all makes me uncomfortable.)
(Alright, let's end this little exploration. Next is testing my raw strength. My flying speed increased significantly—hopefully my raw power did too.)
Unable to bear the silence and loneliness enveloping space, Charlie quickly shot back toward Earth.
*WHOOSH!*
His body soon re-entered Earth's atmosphere. Friction with increasingly dense air molecules created tremendous heat. At first, only orange flashes appeared around his body, but in an instant, Charlie turned into a blazing fireball, like a living meteor streaking toward Earth's surface.
White-blue flames licked around him, leaving a glowing plasma trail in the sky. The temperature around his body reached thousands of degrees Celsius, enough to melt ordinary metal.
The clothes he wore instantly burned to ash, consumed by the extreme heat. But Charlie's body itself remained intact—whether due to his Level 6 physical durability, Armor of Fafnir, or a combination of both.
Instead of burning up like a typical meteor, he only suffered second-degree burns spreading over most of his body.
Landing rather hard in an abandoned field, Charlie immediately raised his hand.
"Dia Fratel!"
Golden light enveloped his body, and in seconds, his blistered and reddened skin healed back to normal.
However, he was now completely naked in the middle of the field. Though no one saw him, embarrassment still struck. Charlie quickly grabbed spare clothes from the Space-Time Cache on his wrist and put them on hurriedly.
"It seems I need to consider making clothes resistant to extreme conditions. Or at least learn a technique to protect clothes when flying at high speeds."