Looking at the poster, Zhang Yu said with a hint of doubt, “Is this the hottest market?”

From the other side, Black Crow continued to send messages: The silver economy, or tutoring classes for the elderly, is currently the most profitable market in the dark tutoring world.

Black Crow: Because the cultivation methods you demonstrated previously were more suited for students and construction sites, they weren’t really appropriate for this market, so you might not have encountered it much.

Black Crow: I’m not sure about your current situation, but since you asked, I’ll tell you about this most profitable market, which is also where our Dark Study Gang is currently in fierce competition with the Golden Class Gang.

Black Crow: The theoretical lifespan limit for Qi Refinement stage is 150 years, so there are a large number of elderly people in Songyang City’s tutoring market.

Black Crow: The elderly have a certain amount of savings, and to avoid being phased out by the market, they need to continuously cultivate and learn new versions and updated cultivation methods to keep up with the times and maintain their jobs.

Black Crow: As a result, the elderly tutoring market has always been in high demand and is very lucrative.

Black Crow: However, the demands of the elderly tutoring market are also very high. After all, those who live to old age and continue working are often peak Qi Refinement practitioners with many years of experience. The lessons they seek are certainly not for basic cultivation methods, but rather many high-difficulty techniques.

Black Crow: In addition to new versions of cultivation methods required for work, longevity techniques, methods to metabolize drug toxins after years of medication, and techniques to heal hidden injuries are all very popular.

Black Crow: After all, only by ensuring good health and overcoming the damage caused by years of medication and overtime can they remain competitive in the workplace.

As Zhang Yu read the messages from Black Crow, he gained a basic understanding of what was most profitable in the dark tutoring world.

He thought to himself, “That makes sense. As the number of university, college, and high school graduates increases each year, the number of elderly Qi Refinement practitioners will definitely grow. These seniors have more savings than young people, and the cultivation methods they need to learn are more expensive. This truly is a huge market.”

Zhang Yu immediately asked again: “Is there a market for the Spring-Autumn Unending Chan?”

Black Crow: “Immortal Rhyme Group’s Spring-Autumn Unending Chan? Haha, of course there’s a market! Teacher Ma, do you know this top-tier cultivation method?”

The Dark Study Gang was backed by the Deep Sea Education Group, an opponent of the Immortal Rhyme Group, and had always enjoyed cracking and pirating Immortal Rhyme Group’s cultivation methods.

As a top-tier expert-level body cultivation method that also enhanced metabolism and eliminated drug and pill toxins, the Spring-Autumn Unending Chan immediately piqued Black Crow’s interest like a cat smelling fish, the moment he heard Zhang Yu, using the alias Ma Yunteng, mention it.

Black Crow: “In three days, the gang will arrange trial lessons for several prospective gold-medal teachers. Teacher Ma, if you’re interested, I can arrange a spot for you.”

Zhang Yu and Black Crow set a trial lesson for three days later. Bai Zhenzhen, standing nearby, frowned and said, “I don’t seem to have any cultivation methods suitable for teaching the elderly.”

Fu Ji said, “A’Zhen, you possess a true spiritual root and have thunder spiritual power infused into your Dantian Qi Sea. Your most suitable path to becoming stronger is ultimately through combat.”

“The current gang war between the Dark Study Gang and the Golden Class Gang is very suitable for you. Not only can it earn you money, but it can also hone your combat skills and prepare you for the Foundation Establishment exam in three months.”

“In my opinion, the best arrangement for both of you is for Zhang Yu to become a gold-medal teacher and give lessons, while you participate in gang battles to hone your strength and earn money.”

Zhang Yu frowned and asked, “Gang wars… won’t they be dangerous?”

Fu Ji replied, “Nonsense, how can real combat be without danger? But compared to battles involving true military-grade power, corporate wars, or your future struggles against the evil god cultists behind the Zhou family, the intensity of gang battles is definitely quite low.”

“If you’re unwilling to take even this small combat risk, how do you expect to rise?”

Bai Zhenzhen, standing nearby, nodded, a determined glint in her eyes. “Fu Ji is right.”

“This path truly suits me.”

“Yuzi, don’t worry. With the true spiritual root assisting me and my speed, even if I encounter someone I can’t defeat, can’t I still run?”

Zhang Yu looked deeply at Bai Zhenzhen, knowing this was the path she had chosen for herself, her decision, and her resolve to pass the Foundation Establishment certification. As a close friend, he could only respect her choice.

So Bai Zhenzhen also logged into Kun God World, added Black Crow as a friend, and joined the Dark Study Gang’s battles under her original alias, Le Mulan.

Black Crow: “Teacher Le, your timing is perfect. The gang is currently in need of an expert like you. There’s an operation in four days, are you interested in participating?”

After finalizing their arrangements with Black Crow, Zhang Yu and Bai Zhenzhen fully dedicated themselves to their respective cultivation, preparing for the upcoming lessons and battles.

Three days passed in the blink of an eye.

During these three days, bolstered by the High School Saint Physique, Zhang Yu first cultivated the Resentful Fiend Technique to Level 10, developing a body covered in copper-armor corpse skin.

Once this cultivation method reached Level 10, when he circulated his energy, a bronze color would appear beneath his skin, as if he were wearing a layer of armor.

He tried cutting the skin on the back of his hand with a small knife; it required more than 30% of his strength to produce even a slight trace of blood.

It felt as if he were cutting into a thick, hard layer of keratin, even though it was his own skin.

Evidently, after cultivating the Resentful Fiend Technique, Zhang Yu’s skin possessed far greater toughness and protective power than before.

After cultivating this Resentful Fiend Technique to Level 10, he still felt a sense of incompleteness, as if there was more to achieve.

Fu Ji, standing by, advised, “This Resentful Fiend Technique should have subsequent versions.”

“However, what you bought was only the right to use the Qi Refinement version.”

“If you want to continue cultivating this method after reaching Foundation Establishment, pushing it to Level 20, then you’ll need to purchase the right to use the Foundation Establishment version.”

Zhang Yu wasn’t particularly interested in this, as Fu Ji didn’t know he was cultivating so many methods to form a Martial Dao Saint Embryo. He hadn’t yet considered what cultivation methods he would practice during the Foundation Establishment stage.

Over these three days, besides refining his skin with the Resentful Fiend Technique, Zhang Yu also borrowed Bai Zhenzhen’s Mysterious Thunder Electric Moxibustion Needle Set to help him cultivate the expert-level technique, “Thunderbolt Marrow Cleansing Scripture,” which he had obtained from Songyang High School.

This Thunderbolt Marrow Cleansing Scripture was a top-tier body cultivation method that used electric shocks to stimulate bone marrow generation and accelerate bone remodeling, thereby increasing bone density.

The Mysterious Thunder Electric Moxibustion Needle Set from Songyang High School could even be said to have been acquired specifically to complement this cultivation method.

Zhang Yu had 999 silver needles inserted all over his body, and bolts of thunder coursed through his bone marrow, reshaping his bones according to the methods of the Thunderbolt Marrow Cleansing Scripture.

As Zhang Yu progressed the Thunderbolt Marrow Cleansing Scripture from Level 1 to Level 9, all the bones in his body, except for his skull, had been renewed, emitting a silvery-frost-like sheen beneath his skin and flesh.

At this very moment, as Zhang Yu finally pushed the Thunderbolt Marrow Cleansing Scripture to Level 10, his skull seemed to undergo thousands of refinements in an instant, also turning a silvery-frost color.

As the bones throughout his entire body were renewed, his bone density and strength surged. Zhang Yu’s weight also increased with the growth in bone mass, reaching over 300 kilograms suddenly, despite little change in his physical build.

The Level 10 effect of the Thunderbolt Marrow Cleansing Scripture allowed him to slowly repair bone injuries by circulating this cultivation method.

Patting his chest, Zhang Yu felt that the skin refined by the Resentful Fiend Technique, combined with the ribs strengthened by the Thunderbolt Marrow Cleansing Scripture, enveloped his internal organs like a double layer of armor.

At this moment, Zhang Yu’s physical strength finally crossed the last threshold, reaching Level 10, the limit for the Qi Refinement stage.

“Although my physical strength only increased by about 0.06 levels.”

“But these two body-protection cultivation methods have made my strength far surpass what it was before.”

“Indeed, once the Qi Refinement stage’s Dao Heart, spiritual power, and physical strength all reach their limits, cultivating more methods becomes the best way to enhance one’s power.”

Looking at A’Zhen, who was still cultivating nearby, Zhang Yu spoke to the Mysterious Thunder Electric Moxibustion Needle Set, “Spirit, stop cultivation mode.”

The spirit’s voice came from within the needle box: “Cultivation mode stopped. Entering standby. Awaiting user command.”

With flashes of electric light, the 999 silver needles shot out from Zhang Yu’s body and returned, one by one, into the needle box.

Twisting his neck and listening to the crackling sounds from his newly formed bones, Zhang Yu smiled slightly and said, “A’Zhen, you continue your cultivation. I’m off to the trial lesson.”

Bai Zhenzhen waved her hand and said, “Good luck, earn more.”

The meeting point Zhang Yu had arranged with Black Crow was in an abandoned underground transit station.

Zhang Yu, having altered his appearance, arrived at the station and soon saw a young girl standing in front of Black Crow, discussing something with him.

Zhang Yu had no interest in eavesdropping. He turned his head, intending to move aside and wait.

However, he heard the girl say furiously, “Teacher! My grandpa secretly watches pornography as soon as class starts, always secretly watching pornography! When I open his phone, it’s full of it, there’s no space left even for textbooks!”

The girl’s words made Zhang Yu immediately stop.

The girl continued, “Because he’s not serious in class and his cultivation progress can’t keep up, his work performance has been declining for several months!”

“My grandpa has been undisciplined since he was young. My dad says that when my grandpa worked, he never wanted to work overtime, and he hadn’t been promoted even by the time he was 50, unable to afford my dad’s and my tutoring fees.”

“So I’m begging you, please help keep a closer eye on him so he can keep up with his cultivation and earn more money.”

“We won’t waste this money; we’ll save it all for you. We’ll come to your place for tutoring in the future.”

Black Crow said helplessly, “Our teachers here are very busy and generally not responsible for classroom discipline.”

After the two argued for a while, class finally ended in the nearby classroom, and the girl had to go pick up her grandfather.

Only then did Black Crow breathe a sigh of relief, look at Zhang Yu who was standing nearby, smile, and say, “Teacher Ma, you’ve arrived.”

Zhang Yu asked curiously, “The one just now…”

Black Crow casually explained, “Oh, that was a student who has been on long-term medication and whose intelligence declined in old age. His family has low education and income, and they all hope this intellectually challenged student can continue to earn money, so they sent him here.”

Black Crow continued, “Just a reminder, today’s trial lessons are real classes, and you’ll be facing real elderly clients.”

“What class are you planning to teach?”

Zhang Yu calmly replied, “Spring-Autumn Unending Chan.”