Rain had thought the trouble with birth parents had faded, so he searched the Old World Rules sites for books explaining the laws of the world before the Cataclysm.
After advancing to a true body and gaining the ability to absorb radiation energy from his surroundings, he finally understood why C-rank Genetic Warriors had to learn about the Old World Rules—a requirement that initially seemed unnecessary.
Advancing to B-rank as a Genetic Warrior requires combining two Old World Rules with one rule from the New World. Alternatively, a breakthrough can be achieved if one's understanding of a New World rule crosses a certain threshold.
However, C-rank Genetic Warriors now use a fusion of three rules to reach that same threshold. Rain now understood the reason behind this necessity.
After the Cataclysm, radiation energy flooded the world, transforming every material into a source of radiation. Simultaneously, a strange energy from beyond the world began corrupting the radiation. After a thousand years, the distinction between radiation energy and weird energy had blurred to the point where they were almost indistinguishable.
The New World Rules, too, have been corrupted to some extent by the "weird energy." In contrast, the Old World Rules, grounded in the strict rigor of mathematics, have remained untouched by this corruption.
These Old World Rules have the unique ability to purify radiation energy. When a Genetic Warrior advances to A-rank, they gain the ability to purify the world itself.
As a result, a universal rule has been established among all human forces: no A-rank Genetic Warrior can be killed. They may be imprisoned, but their lives must never be harmed.
They have to purify the radiation energy in the world. Once this purification is complete, future Genetic Warriors will no longer need to understand the Old World Rules.
Rain's initial understanding of sharp rules originated from the clone in the Star Immortal World and its comprehension of the Way of the Sword. However, when he purchased a basic book explaining the sharp rules, he was astonished.
The thousand-page book, apart from the introduction and table of contents, was filled with mathematical formulas and theorems he had never encountered before. Yet, inexplicably, he could understand some of them.
After careful consideration, Rain realized this was because the formulas and theorems explained the Rule of Sharpness, a concept he had already grasped about 50% of, as required in the True Body realm.
Since the book was intended for those in the True Body realm, his existing understanding of sharpness allowed him to instinctively comprehend parts of the formulas and theorems. Even so, Rain chose to start reading the book from the beginning, steadily deepening his understanding as he progressed.
With his full attention focused on the book, Rain lost track of time. Now that his body could absorb radiation energy, he was able to sustain himself without external nourishment.
His genetic energy reserves were already full, and the slight transformation his body had undergone after advancing to the True Body realm allowed him to survive for about a week without food or sleep, with no adverse effects.
Since he wasn't engaging in any combat, every second he passively absorbed radiation energy and converted it into genetic energy, further extending the duration he could go without sustenance.
After two days, Rain let out a sigh of relief. Without opening his eyes, he spread his senses outward. He could feel the rules of the world around him.
Among them, he identified the rules of sharpness, and with the help of the formulas and theorems from the book, he began to grasp them on a deeper level. Six hours later, he opened his eyes, sensing a slight advancement in his realm. His progress, however, remained at around 49%.
Rain was forced to halt his practice when, for the past five minutes, his B.I.T. device had been pinging incessantly. Checking his inbox, Rain discovered that he had received about 20 messages over the past two days. After reading through them, his eyes turned sharp, and a chilling killing aura radiated from him.
The first seven messages were from the hospital where his siblings had been transferred. Their new doctor was none other than Helena, Helen's mother. She had taken on their case specifically because of him, and it appeared only she could heal them. However, she had called for a meeting with Rain to discuss something important.
The remaining messages were from Siobhan, the Guard Headquarters, Sky, and Damian. These messages revealed grim news: Lily and Siobhan had managed to uncover the culprit behind their case, but the culprit was at the initial C-rank level.
During their confrontation, the culprit seriously injured Lily, leaving her in a coma. Lily had taken the brunt of the attack, while Siobhan was only slightly injured.
The two had survived only because a C-rank Guard robot had been stationed a short minute away from their location. While a C-rank robot was no match for the culprit, it had managed to hold them off long enough for reinforcements to arrive. Unfortunately, the culprit escaped.
The Guard Headquarters was now requesting Rain's assistance, as no Genetic Warrior in the town was strong enough to face the culprit. Rain quickly replied, confirming that he would go. Meanwhile, Sky and Damian had also messaged him, urging him to head to the town immediately and eliminate the culprit.
Rain quickly got dressed and stepped into the car waiting at the front of his building. He instructed the B.I.T. to drive to Helen's home on the surface level of the city.
Twenty minutes later, he arrived at Helen's house, where the door opened before he even had a chance to ring the bell. Helen was standing there, waiting for him. However, she avoided meeting his gaze and kept a noticeable distance from him.
Rain, with his mind consumed by worry over Siobhan and Lily, paid little attention to Helen and walked straight into her mother's office. After exchanging brief greetings, he sat down across from her.
Helen's mother spoke first, saying, "I can heal your siblings, but I need you to do something for me. It won't harm you—in fact, it will benefit you."
Rain was confused. If the price was too high, he was prepared to refuse. Having been separated from his parents at birth and never truly connecting with his siblings, he didn't feel close to them. If asked to choose between saving Luke—his school rival—or his siblings, he would likely choose Luke, as their bond was stronger despite their rivalry.
"What do you need me to do?" Rain asked cautiously.
Helen's mother replied, "I've sent you a research paper. After reading it, you'll understand what I need from you."
Rain opened the file and saw that the research paper was 247 pages long. He realized he didn't have the time to read it now, as the journey to Blood Mushroom Town would take six hours.
"Can I read it later and give you an answer? I have an urgent mission in Blood Mushroom Town, and I need to leave now. I'll read the paper on the way," he said.
Helen's mother nodded in agreement. Rain quickly greeted her and Helen before rushing out of the house. He got into the car, and it sped off toward the town.
On the road, with the city fading into the distance behind him, Rain initiated a video call with Siobhan. After a few seconds, her haggard face appeared on the car's dashboard screen.
Rain: How are you?
Siobhan (tears welling in her eyes): I'm okay, but Lily… she's in a coma. She shielded me to protect me.
Rain: Don't worry, I'm on my way. Can you tell me more about the culprit?
Siobhan: The culprit is from our country, but we don't know his name. He isn't a genetic user; he's a weird energy controller. He's been killing people as blood sacrifices for his weird weapon.
When the guard robot confronted him, it scanned him and confirmed his strength to be at the initial C-rank genetic warrior level. His lifespan is also very short, which could explain why he's killing people—he's likely using their lives to power his weapon and extend his own.
Rain: Then stay safe. I'm coming. The culprit won't live for long.
With that, he ended the call.
Rain pondered the situation. In his current realm of the intermediate True Body, his strength was roughly equal to that of the culprit. On his own, he might not be able to kill him, but with the assistance of the C-rank guard robots in the town, the task would be much easier.
The culprit, however, hadn't fled the town after attacking Lily and Siobhan. This became clear when, two hours later, a family of four was brutally murdered. The crime scene bore the same unmistakable signs as the culprit's previous attacks.
As Rain looked at the night scenery outside the car, he estimated that he would arrive in the town around midnight. Closing his eyes, he began reading the research paper sent by Helen's mother. Within half an hour, he had finished it and understood what Helen's mother wanted from him.
She wanted him to marry Helen and engage in double cultivation with her. Both his and Helen's genetic medicines originated from a pair of super-healing lizards.
These lizards possessed an additional ability: mates could connect their minds and share their understanding of rules with each other. According to Helen's mother, connecting his mind with Helen's would increase his chances of advancing to A-rank by 30%.
However, Rain knew he didn't need this boost—he was confident he would reach A-rank on his own. With the knowledge he had gained from two additional worlds, he had advanced to the intermediate True Body realm in just two months.
His spirit had grown significantly when he reached peak D-rank, but he had refrained from forming clones in the additional worlds. He had decided to wait until advancing to C-rank, as a stronger spirit allowed for faster comprehension of rules.
If he were to marry, he would choose Siobhan. Though he had once felt an attraction to Helen, he realized it stemmed from the genes of the super-healing lizard within him. That attraction vanished completely when the genes fully merged with his body. Without hesitation, he sent a short reply to Helen's mother: No.
He wouldn't sacrifice his future happiness for anyone. Pushing the matter out of his mind, he closed his eyes and began focusing on comprehending the rule of sharpness. Strengthening his understanding of the rule would make it easier to eliminate the culprit.
Meanwhile, at Helen's house, she and her mother were drinking tea when her mother received Rain's message.
After reading it, Helen's mother smiled faintly and said, "Rain said no."
Helen, puzzled by her mother's smile, asked, "He said no, and yet you're smiling? Are you planning something?"
Her mother shook her head and replied, "I'm not planning anything, but what he'll experience in the town will make him realize his current rate of progress isn't enough."
Hearing this, Helen, aware that Rain was heading to Blood Mushroom Town for a mission, grew concerned. "Will something happen to Rain in that town? Should I warn him?"
Helen's mother calmly said, "No, don't. Instead, you should prepare for the wedding in three days."
Helen hesitated. "What if his decision is still no after what happens in the town?"
Her mother's expression didn't waver. "Then someone will make him say yes. This marriage no longer depends on him but on the entirety of Spark Technology." With a smile, she sips her tea.