"Big sis Natalia is the strongest woman of our Dulia town. She helps the orphanage in collecting donations. She teaches combat and adventuring to young people like you. She helps the Dulia town in a lot of ways, that's why we call her the big sister of our town." Rita explained with slight enthusiasm.

"I see, she is quite generous. I will ask her to teach me," Jack said with a smile.

…

Jack arrived in front of the guild. It was a large, three-storied building bustling with adventurers.

Of course, he didn't know the way. Thankfully he had met a young adventurer who kindly guided him to the guild. And as he arrived, everyone attacked him with greetings.

He would have drowned in their greetings and praise had a female attendant not come for his rescue. He was then guided to the guild master's office.

*knock* *knock*

"Come in!"

Jack entered a spacious room. There was a large table behind which sat the guild master Albert. A lot of papers were piled upon it. There were wooden sofas on either side of the room and a large wooden cabinet in a corner. The room gave typical office vibes with the smell of papers.

The large windows on either side of the room did a good job of illumination and ventilation, making the atmosphere quite comfortable.

"Welcome Jack, come, have a seat." Alber greeted him with a smile. He returned the greeting as he sat on the chair.

"Young man, I won't let you go unless you tell me the whole story," Albert said with a big smile, "but before that," he took out a metallic card and handed it to Jack.

"Put a drop of blood on it."

He bit his finger and dripped blood onto the card. A moment later, it glowed and displayed some information which he couldn't read. Not intending to appear a fool, he gave a big smile and thanked the guild master, "Thank you!"

"Don't mention. As you have slain a wyvern, you deserve the highest rank, the 'S' rank, but I don't have the authority to grant it. That's why you received an 'A' rank, the highest I could grant." Albert said as he took out a letter.

"When you go to the capital, hand this letter to the guild master of the main branch, he will consider improving your rank."

Albert then took out a spatial pouch, "And this is the reward issued by our guild and the mayor. It's 250 gold coins."

250 gold coins are quite a generous reward. Jack had received the basic knowledge regarding the currency from his mother, so he knew. 

"Thank you!" Jack's heart was jumping in joy.

"Haha, and one more thing…" Albert gave him a large beast core. "Um, we are not capable of compensating you for this core, haha. When you go to the capital, you can sell it there to get a good price. It will fetch at least 2000 gold," he said as a matter of fact.

Jack's eyes sparkled, "Beast cores are that valuable?" he asked. If that's the case, it would be a lucrative business for him. It just requires killing some beasts which is not a big deal.

"Not all, the one you have is one of the highest-ranked beast cores, so it is quite valuable."

"Oh, and what is it used for?" Jack asked curiously.

"A beast core handles the whole mana system of a beast, so it is formed with quite an intricate design of the mana vein network. It can be processed and used in creating medicines, and also magic staffs that can amplify the magic output of the user. But it contains a lot of impurities and cannot be directly utilized. So it has to be processed and purified to convert it into a magic crystal."

"It goes through a tedious process of purification and transforms into a transparent crystal, called a magic crystal." Albert paused.

"Magic crystals are a lot more valuable than an impure beast core. If the one in your hands is purified, it can even fetch a price as high as 10,000 gold."

Jack raised his eyebrows in surprise. He hadn't known its value in the past. He had defeated many beasts and obtained many beast cores. He had even absorbed the energy contained within them. They would turn into beautiful transparent crystals after absorption. He had guessed them to be valuable and had planned to carry and sell them.

But he didn't have anything like spatial treasures to carry them. When he had to cross the huge river, he had to fight the troublesome river monsters. By the time he arrived at the shore, his huge sack of magic crystals was already gone.

And yesterday, due to his happiness and excitement, he offered the whole wyvern for free without thinking much about its value. It's thanks to the guild master and the mayor being kind, he didn't suffer a loss.

Jack observed the beast core. It was about 10cm in diameter, smooth and round with a deep translucent blue color. It had a bunch of green veins inside intertwined to form something akin to a web.

Jack could sense the mana flow inside. So he grabbed it with both of his hands and started sucking the mana inside it. It wasn't new to him as he would do the same with the cores he would obtain in the forest. It had helped him heal his wounds and energy. He had found it pretty convenient.

In just a minute, he sucked the core dry, turning it into a transparent magic crystal right in front of the guild master.

Albert watched a beast core turning into a magic crystal in just a minute. He couldn't believe what he saw. It took him a while to process what just happened as he blankly stared at it.

"How's it?" Jack asked, waking him from his stupor. Jack wanted to confirm if this was the magic crystal he was talking about.

"Huh...? D-did you just purify a beast core?" Albert took the purified beast core and started observing it. "Damn! It has the highest purity I have ever seen...!" He observed it like a little kid with an excited smile. "How did you do that?"

"What's the big deal? I just absorbed its energy." Jack replied casually.

"Big deal? This is a big deal! Who absorbs energy like this? And young man, it takes days to refine a beast core, and that too, with lower purity than this. Chances of refining high purity magic crystals like these are a lot low. And you just refined it in a minute?"

"This… I think this can amplify magic output by almost 100 percent. This is amazing!" Albert continued. His eyes sparkled as he looked at Jack with a crafty smile.

Jack had a bad feeling. He felt like he had hit his own leg. That's what would happen after showing off.

"Jack, my dear friend, how many other secret abilities do you have?!"

Jack's face turned unsightly, "N-no, that was the last… and what ability? I thought it was obvious!" As he was transmigrated, he thought that such a thing was obvious. He lacks a lot of basic knowledge, he thought, as he decided to learn properly so that no one would be able to take advantage of his ignorance. Just like what this guild master would do now.

"We have a lot of beast cores!" And it came.

"Haha! Don't worry, I will pay you properly. If you can refine it with such purity, it will fetch a high margin. Don't you want to earn money?"

"30 percent of net profit! No less." Since he has already fallen into the trap, he should at least try to snatch some benefits. So he made a demand. A business is not a one-way thing, and a contract won't form without the compromise of both parties. Especially this contract where he holds a greater advantage due to his ability.

Albert raised his eyebrows. Thirty percent is a high demand considering the supply and selling that will be done through the guild's vast network. But it still would be a lot more profitable considering the purity.

"20…" yet he still tried to lower it.

But before he could say anything further, Jack interrupted, "Not a single percent less than 30. And make sure to make a written contract with one-month validity," he said as he smirked.

He came from modern earth where every organization diligently tries to rob people at every step. How would he let this guild master take the advantage?

"Young man, you are taking advantage of my kindness!"

That was true. Because of his previous ignorance, he had offered the whole wyvern without thinking. If Albert hadn't returned the core, he wouldn't have known. But that doesn't mean he would let go of such an opportunity.