Looking at the poster, Zhang Yu was skeptical and said, “This is the hottest market?”

On the other side, Black Crow had already sent another message: “The silver-haired economy, senior citizen cram schools, are currently the most profitable market in the dark cram school world!”

Black Crow: “Because the cultivation methods you showed before were more suitable for students and construction sites, they’re not very suitable for this market, so you might not have encountered it much!”

Black Crow: “I’m not sure about your current situation. Since you asked, I’ll tell you about this most profitable market, which is also where our Dark Learning Gang is fiercely competing with the Golden Lesson Gang!”

Black Crow: “The theoretical lifespan limit for the Qi Refining stage is 150 years, so there are a large number of elderly people in Songyang City’s cram school market!”

Black Crow: “The elderly have some savings, and in order not to be eliminated by the market, they need to constantly cultivate and learn new versions and updated cultivation methods to keep up with the times and maintain their jobs!”

Black Crow: “Therefore, the elderly cram school market has always been in short supply and very profitable!”

Black Crow: “It’s just that the requirements for the elderly cram school market are also very high. After all, those who can live to old age and continue working are all veteran Qi Refining peak cultivators. The cram schools they need are definitely not for basic cultivation methods, but for many high-difficulty ones!”

Black Crow: “In addition to new version cultivation methods needed for work, there are also longevity cultivation methods, cultivation methods to metabolize drug toxins after taking medicine for many years, and cultivation methods to repair hidden injuries in the body… all of these are very popular!”

Black Crow: “After all, only by ensuring good health and overcoming the damage caused by years of taking pills and working overtime can they continue to ensure their competitiveness in the workplace!”

Looking at the messages sent by Black Crow, Zhang Yu had a basic understanding of what was most profitable in the current dark cram school world!

He thought to himself, “That’s right, as the number of college students, junior college students, and high school graduates increases year by year, the number of Qi Refining seniors will definitely increase. These seniors have more savings than young people, and the cultivation methods they need to learn are more expensive than those for young people. This is indeed a huge market!”

Zhang Yu immediately asked: “Is there a market for the ‘Spring Autumn Endless Zen’?”

Black Crow: “The Immortal Rhyme Group’s ‘Spring Autumn Endless Zen’? Haha, of course there’s a market. Master Ma, do you know this top-tier cultivation method?”

The Dark Learning Gang is backed by the Deep Sea Education Group. As a rival of the Immortal Rhyme Group, they have always been most keen on cracking and pirating the Immortal Rhyme Group’s cultivation methods!

And ‘Spring Autumn Endless Zen’, as a top-tier expert-level body refining cultivation method, also has the effect of enhancing metabolism and eliminating drug and elixir toxins. As soon as Black Crow heard Zhang Yu (using the pseudonym Ma Yunteng) mention ‘Spring Autumn Endless Zen’, he was like a cat smelling fish, and his interest greatly increased!

Black Crow: “In three days, the gang will arrange for several candidate gold medal teachers to give trial lectures. If you’re interested, Master Ma, I can arrange it for you!”

Zhang Yu agreed with Black Crow about the trial lecture in three days. Bai Zhenzhen, who was beside him, frowned and said, “I don’t seem to have any cultivation methods suitable for teaching the elderly!”

Fu Ji said, “Ah Zhen, you have a True Spiritual Root and thunderous mana infused into your dantian and qi sea. The path to becoming stronger for you is ultimately combat!”

“And the gang war between the Dark Learning Gang and the Golden Lesson Gang is very suitable for you right now. Not only can it make you money, but it can also hone your combat skills and prepare you for the Foundation Establishment exam in three months!”

“In my opinion, Zhang Yu should go and be a gold medal teacher, and you should participate in gang battles, honing your strength while earning money. This is the most suitable arrangement for the two of you!”

Zhang Yu frowned and said, “Gang war… is it dangerous?”

Fu Ji said, “Of course it’s dangerous! But compared to real military-grade combat, compared to company wars, and compared to your future battles with the evil god believers behind the Zhou family, the intensity of gang battles is definitely very low!”

“If you don’t dare to take even this small risk in actual combat, how do you expect to climb up?”

Bai Zhenzhen nodded, a hint of determination flashing in her eyes: “Fu Ji is right! I’m indeed suitable for this path!”

“Yu Zi, don’t worry, with the True Spiritual Root to assist me and my speed so fast, even if I encounter someone I can’t beat, can’t I just run away?”

Zhang Yu looked at Bai Zhenzhen deeply, knowing that this was the path she had chosen herself, it was her decision, and it was the determination she had made in order to pass the Foundation Establishment exam. As her close friend, he could only respect her decision!

So Bai Zhenzhen also went to the Kun God World, added Black Crow as a friend, and participated in the Dark Learning Gang’s gang battles using her original pseudonym, Le Mulan!

Black Crow: “Teacher Le, you’ve come at the right time. The gang is currently short of experts like you. There’s an operation in four days, I wonder if you’ll participate?”

After making an agreement with Black Crow, Zhang Yu and Bai Zhenzhen devoted themselves wholeheartedly to their respective cultivation, preparing for the upcoming lectures and battles!

In the blink of an eye, three days passed!

In these three days, with the blessing of the High School Sacred Body, Zhang Yu first cultivated the ‘Grievous Corpse Art’ to level 10, forging a body of copper-armored corpse skin!

When this cultivation method reached level 10, his skin would turn bronze when he exerted his strength, as if he was wearing a layer of armor!

He tried cutting the skin on the back of his hand with a knife, and it took more than 30% of his strength to create a slight bloodstain!

Even though he was cutting his own skin, it felt like he was cutting through a thick and hard layer of keratin!

Clearly, after cultivating this ‘Grievous Corpse Art’, Zhang Yu’s skin possessed far more toughness and protection than before!

After cultivating this ‘Grievous Corpse Art’ to level 10, he still felt a sense of unfinished business!

Fu Ji pointed out from the side: “This ‘Grievous Corpse Art’ should have subsequent versions!”

“However, you only bought the usage rights for the Qi Refining version!”

“If you want to continue cultivating this cultivation method after Foundation Establishment and push it to level 20, you’ll have to buy the usage rights for the Foundation Establishment version!”

Zhang Yu wasn’t very interested in this, after all, Fu Ji didn’t know that he was cultivating so many cultivation methods in order to form a Martial Dao Sacred Embryo. He hadn’t thought that much about what cultivation methods to cultivate in the future Foundation Establishment stage!

In these three days, in addition to refining his skin with the ‘Grievous Corpse Art’, Zhang Yu also borrowed the ‘Mystic Thunder Acupuncture Needle Set’ from Bai Zhenzhen to assist in cultivating the expert-level cultivation method ‘Thunderbolt Marrow Cleansing Scripture’ that he had obtained from Songyang High School!

This ‘Thunderbolt Marrow Cleansing Scripture’ uses electric shock to help the bone marrow regenerate and accelerate bone remodeling. It is a top-tier body refining cultivation method that can enhance bone density!

And the ‘Mystic Thunder Acupuncture Needle Set’ from Songyang High School can be said to have been obtained by Songyang High School specifically to complement this cultivation method!

Zhang Yu was covered with 999 silver needles, and streams of lightning coursed through his bone marrow, reshaping his bones with the ‘Thunderbolt Marrow Cleansing Scripture’!

In the process of Zhang Yu pushing the ‘Thunderbolt Marrow Cleansing Scripture’ from level 1 to level 9, all the bones in his body except his skull had been renewed, emitting a silver frost-like luster under his skin!

At this moment, when Zhang Yu finally pushed the ‘Thunderbolt Marrow Cleansing Scripture’ to level 10, his skull seemed to have undergone a thousand hammer blows in an instant, and it also became a piece of silver frost!

As all the bones in his body were renewed, and his bone density and bone strength soared, Zhang Yu’s weight also increased with the weight of his bones, reaching more than 300 kilograms without much change in his body shape!

The level 10 effect of the ‘Thunderbolt Marrow Cleansing Scripture’ also allowed him to slowly repair damage to his bones by circulating this cultivation method!

Patting his chest, Zhang Yu felt that the skin and flesh tempered by the ‘Grievous Corpse Art’, plus the ribs tempered by the ‘Thunderbolt Marrow Cleansing Scripture’, were like double armor, protecting his internal organs!

At this moment, Zhang Yu’s physical strength finally crossed the last step and reached the limit of Qi Refining stage, level 10 physical strength!

“Although the physical strength only increased by about 0.06 levels!”

“But these two body protection cultivation methods make my strength far surpass what it was before!”

“Sure enough, after the Dao Heart, mana, and physical strength of the Qi Refining stage all reach the limit, cultivating more cultivation methods is the best way to improve strength!”

Looking at Ah Zhen, who was still cultivating beside him, Zhang Yu said to the ‘Mystic Thunder Acupuncture Needle Set’, “Spirit, stop the cultivation mode!”

The spirit’s voice came from the needle box: “Stopping cultivation mode, starting standby, waiting for user commands!”

999 silver needles flashed with electric arcs, shot out of Zhang Yu’s body, and all returned to the needle box!

Twisting his neck, listening to the crackling sound coming from his new bones, Zhang Yu smiled slightly and said, “Ah Zhen, you continue to cultivate, I’m going to the trial lecture!”

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

The location Zhang Yu agreed to meet Black Crow was in an abandoned underground subway platform!

Zhang Yu changed his appearance and had only just arrived at the platform when he saw a girl standing in front of Black Crow, discussing something!

Zhang Yu had no intention of listening to gossip. He turned his head and planned to wait aside!

But he heard the girl say angrily, “Teacher, my grandpa secretly watches movies during class. Every time I open his phone, it’s all movies. There’s no room left to store the textbooks!”

The girl’s words made Zhang Yu stop immediately!

The girl continued, “Because he doesn’t study hard in class, his cultivation progress can’t keep up, and his work performance has been declining for several months.”

“My grandpa has never been self-disciplined since he was a child. My dad said that my grandpa didn’t want to work overtime when he was working, and he hadn’t been promoted by the time he was 50. He couldn’t even afford my dad’s and my cram school fees!”

“So, I beg you, please help keep an eye on him so that he can keep up with his cultivation and earn more money!”

“We won’t spend this money indiscriminately. We’ll save it all for you, and we’ll come to your house for cram school in the future!”

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

After arguing for a long time, class finally ended in the classroom next door, and the girl had to pick up her grandpa from school!

Black Crow finally breathed a sigh of relief, looked at Zhang Yu standing aside, smiled, and said, “Teacher Ma, you’re here!”

Zhang Yu asked curiously, “That just now…”

Black Crow casually explained, “Oh, that’s a student who took medicine for a long time and has a reduced IQ in old age. His family has low education and low income. They all hope that this mentally challenged student can continue to earn money, so they sent him here!”

Black Crow continued, “Let me remind you, today’s trial lecture is a real classroom, and the people you’ll be facing are all real elderly clients!”

“I wonder which class you plan to teach?”

Zhang Yu said indifferently, “‘Spring Autumn Endless Zen’!”