Chapter Ten: The Supreme Mage's Ultimate Magic

"Riemannian geometry and Einstein field equations?"

Chen Yu’s eyes widened in disbelief as he sat bolt upright on his bed.

"That’s what she told me, anyway." Shang Lu sat on the edge of his own bed, head bowed as he wrung out a towel. Hot water dripped rhythmically into the basin. He stared blankly at the water below, and after a long moment, he let out a melancholy sigh. "Tell me, is this my inescapable fate? Why did no one tell me before I came here? Do I really have to study general relativity after graduation?"

"You're a top student, Chief Engineer," Chen Yu comforted him. "You can handle it."

"Did you study general relativity in college?" Shang Lu tilted his head, his tone fierce.

"No... no," Chen Yu replied. "We didn't take that. It sounds terrifying."

"It’s even more terrifying to study. Hardly anyone can master this stuff. Even Director Ji doesn't understand it; he's an engineer, not a theoretical physicist. Damn it... if he doesn't even know it himself, why does he want me to learn it? When I took the elective on the foundations of general relativity, a single course in tensor analysis was enough to make me wish I were dead." Shang Lu tossed the towel onto the headboard, kicked off his stinking socks into his shoes, and flopped backward onto his soft pillow, staring straight at the ceiling. "You have no idea what those mecha pilots are actually doing. It’s just too messed up."

"How messed up?"

"Extremely, incredibly messed up."

"Well, Chief Engineer, I wish you the best of luck."

Chen Yu's gaze turned sympathetic.

"On the battlefield against the Angels, being just a pilot is useless," Shang Lu said gloomily. "You have to be a mathematician and a physicist."

Shang Lu’s impression of the mecha had been completely overturned today. He realized that compared to a weapon of war, the mecha was more like a powerful, precision gravity detector combined with a supercomputer. Compared to planes, tanks, cannons, or warships, the mecha was more closely related to the Large Hadron Collider or a high-energy particle accelerator. Shen Jiang was right: Hong Lian was a giant physicist. She needed to contemplate profound and complex physical problems on the battlefield, making immediate analyses and calculations. This was the foundation for effectively striking four-dimensional monsters like the Angels. But how could this be possible?

How could such a war ever exist in human history?

Soldiers holding guns needing to analyze the Dirac equation, perform Lorentz transformations, or juggle other chaotic physical laws while under fire just to find a target—it sounded like they were trying to assemble an army composed of Bohr, Dirac, Riemann, Hilbert, Minkowski, Feynman, and Einstein. Where would they find such soldiers?

But, damn it all, they actually found them.

This was likely the harshest and most difficult selection criteria in human history, requiring pilots to master numerical relativity while simultaneously learning to operate a mecha to fight the Angels.

"God damn it—"

Shang Lu buried his face in his hands and sighed.

No one understood better than Shang Lu what this meant. The Einstein field equations were the core of general relativity, the formulas describing the changes in space and gravity. They were arguably the most complex set of equations in human history. Even Einstein himself could not solve them; they were so complex that finding general or exact solutions was nearly impossible. Yet, mecha pilots were required to analyze and solve them while facing an Angel! Using the massive computing power of a supercomputer to brute-force the Einstein field equations and obtain approximate solutions—this was the core task of a mecha pilot in combat.

It was equivalent to solving an extremely complex system of second-order non-linear partial differential equations while a plane was crashing—an urgent, life-or-death race against time. Succeed, and all is well; fail, and humanity is doomed.

This required the pilot to be a gifted genius in mathematics and physics, possessing deep research and sensitivity in the field of general relativity far beyond that of an ordinary person, perhaps even capable of mental calculation of partial differential equations. Shen Jiang said that such a genius might appear once in every hundred thousand people.

"Truly perverse."

Shang Lu muttered.

Shen Jiang was one such perverse genius.

You really couldn't tell—that young woman of twenty-seven or twenty-eight was actually one of the world's top experts in numerical relativity.

Old Man Ji had reached such an age only to live like Staff Officer Huang (Staff Officer Huang was the Chinese rural dog that Old Man Ji kept).

"What is this? Where is the summation symbol? Oh right, this is the Einstein summation convention... Tensor contraction? How do you contract this?"

Shang Lu muttered to himself, flipping through a large stack of photocopied lecture notes. Chen Yu had taken the basin out to dump the water, leaving him alone in the dormitory. Everyone at Base 151 had their own work and battle stations, but no one was as unique as Shang Lu. He felt that the difficulty of his work was on a completely different level from everyone else's. At the very least, the staff officers at headquarters, the officials in the political department, the assistants in the equipment and logistics departments, and all the workers didn't need to learn how to maintain a mecha after work, let alone Riemannian geometry and general relativity.

Except for the mecha pilots.

Old Man Ji really thought highly of him.

"To hell with tensor analysis!" Shang Lu fiercely slammed the stack of A4 paper onto his bed. "I’m not learning it! I didn't come to 151 for this! I’m not doing it, damn it!"

"Chief Engineer, nothing in the world is difficult for one who sets their mind to it." Chen Yu walked in carrying the basin and wearing slippers, closing the door behind him. "Even if it’s math—"

"Then you learn it." Shang Lu pointed a finger at him.

"It’s not that I don't want to learn, it’s just that a famous predecessor once gave a piece of advice..." Chen Yu said, "Study? Study my ass."

"Let Director Ji find someone else more capable. I really can't grasp this stuff. Engineering and theory, grasping both hands? Both hands must be hard? He doesn't even understand this stuff himself." Shang Lu said, "Starting tomorrow, I’m going to work with the Operations Chief. I’d rather help him design coal-burning aircraft engines..."

Before he could finish, there was a muffled "Boom!" from outside the window.

The courtyard fell silent. A few seconds later, someone in the next building shouted:

"Operations Chief—!"

"It’s nothing! Nothing!" the Operations Chief yelled. "Just added a little too much coal dust! Small problem—!"

Shang Lu let out a long sigh and lay back on his bed like a corpse.

"The great Albert Einstein gave us a powerful weapon, but the difficulty of operating this weapon is so great that few people in the world can master it."

If this were a fantasy world, it would be the ultimate magic left behind by ancient supreme mages to fight against demons—the only way to see through a demon's disguise. But the rules of this magic were so profound that it was difficult to master even with the full extent of human wisdom.

Shang Lu thought of Shen Jiang again. She was the genius warrior who had mastered this ultimate magic, which was why she had to pilot a mecha to fight the Angels.

It sounded truly heroic.

But few people knew that what these heroes had to face inside the mecha cockpit was complex gravitational analysis and equation solving. The usual tropes in stories—sadness, anger, remembering loved ones, shouting out loud, and unleashing a hidden power for a comeback—didn't work here. Because you were facing math, and if you don't know math, you just don't know it.

"Where is the Lighthouse Angel?" Shang Lu turned to ask.

"Still slowly approaching. We estimate it will cross the Level 2 contact buffer zone within three days to a week. We won't know the specifics until the shift handover meeting tomorrow morning." Chen Yu leaned against the headboard and reached out to Shang Lu. "Let me see that thing."

Shang Lu handed him the notes.

He took a glance. "Damn, my eyes are blind."

The next day.

Old Man Ji directed a crane to lift a large, intricately carved aluminum alloy frame. This was the frame for a shield. The frame needed to be light and strong, and aluminum alloy met the requirements. As for the shield material, hafnium carbide ceramic, it had already been sent for high-temperature ablation testing.

151 had built a rocket test stand on the campus of Chongqing University of Posts and Telecommunications. A solid-fuel rocket was mounted on the stand. Of course, the purpose was not to test the rocket engine; they were testing the long-term ablation resistance of high-temperature ceramics. The temperature of the tail flame emitted by a rocket engine could reach four thousand degrees Celsius, which was a suitable testing method. The pentahafnium tetratantalum carbide ceramic tile was lying right under the rocket engine nozzle.

These people were ruthless, burning it under a rocket.

Two hundred meters away, Shang Lu stood in a semi-underground bunker, wearing protective goggles, looking far away at the test stand in the center of the playground.

"Prepare for the test! This is Zero, attention everyone, five-second countdown to ignition—"