"Tell me what you know about mana cores," Bret asked while tinkering with the azure pearl retrieved in the mines.

Bret and Khan had returned home after the events with the Tainted rat. They were both getting ready for the transplant, and Bret took that chance to instruct his son about mana.

"Humans gain access to mana once they obtain a mana core," Khan explained. "They gain the ability to manipulate that mystical energy to enhance physical prowess and create magic."

"Very basic and not entirely right," Bret sighed. "I guess this is my fault. I didn't expect you to grow up so quickly. I should have taught you more long ago."

Bret stopped studying the mana core and raised it toward the artificial light in the room. The pearl shone brighter under that glow, and an azure halo soon covered both him and Khan.

"This is a mana core that has once belonged to a Nak," Bret explained. "Those aliens are literally filled with mana. They are the closest existence to that form of energy. They are so in tune with that power that this organ has become obsolete for them.

"Instead, humans need it to activate their connection to the mana that fills the universe. We are an inferior species in terms of evolution, but our foundation is sturdier. Some extraordinary commanders have grown past the Nak and reached levels that those aliens have never touched."

Khan nodded as excitement built in his mind. He had watched many shows and documentaries that explained those things, but everything felt more real when his father described it.

"You won't immediately gain access to mana once the transplant ends," Bret continued. "Humans need training, and body and mind have different methods. You know I can't say much due to the restrictions of the Global Army, so trust me for now."

Khan nodded again. His father knew so much that the Global Army had used magic items to apply limits to his knowledge. Bret still recalled everything, but he couldn't share certain secret topics with the world.

Bret heaved a helpless sigh when he saw his son's excitement, but he forced himself to continue the explanation. "The Global Army uses synthetic cores of different quality depending on your talent, rank, and so on. This mana core has lost a lot of power in the last ten years, but it's virtually intact. You will basically gain the best core on the market."

Khan could barely contain himself. He only wanted his father to start the surgery, but he respected his desire to explain the subject properly. After all, Bret had often stressed that power was useless without knowledge, especially for humans.

"You said that you could sense the Tainted rat, right?" Bret asked at some point.

Khan didn't hide anything from his father. He had even told him about the faint sensations felt during his hunt for the rat.

"I don't know how to describe it," Khan said. "It felt like a tremor inside my bones."

Bret sighed at those words. "It's possible that you have developed a sensitivity toward mana after the Second Impact. I did my best to suppress every mutation, but you had been in that state for an entire hour before reaching my lab."

"Isn't this mutation a good thing?" Khan asked.

"They never are," Bret explained. "You would have naturally developed this ability with your training. Well, no point recalling those awful days. I guess you will have a few advantages during your first years in the army."

An azure halo suddenly came out of Bret's fingers and enveloped the pearl. The mana core absorbed that energy, and the process captivated Khan.

"Mana gains an element once it enters your body," Bret continued to explain. "This is an innate feature, but don't worry. Every element is strong. How you use it makes all the difference in a battle."

"What element are you?" Khan happily asked.

"Metal, but I've never been too good at magic," Bret replied. "I completed the first level of the warrior training, but the lab was my path. I have never liked fighting."

'Those soldiers would say something very different,' Khan thought before focusing on his father again.

"I can't understand your element without the proper tools," Bret explained. "I'm sorry, but you'll have to wait until you reach the army for that."

"That's fine," Khan replied. "What's the difference between a warrior and a mage?"

Khan was too interested in that knowledge to care about minor delays. Moreover, he couldn't wait to learn true magic. Having enhanced physical strength was cool, but nothing could compare to the ability to launch a fireball or similar skills.

"The training and the abilities," Bret said while scratching his chin covered with an unkempt beard. "Ideally, you should train both body and mind, but you'll understand that eventually. Turn now. The core is ready."

Khan quickly followed his father's directives and turned. Bret kept his neck still and placed the pearl on his nape. Then, a scorching sensation reached Khan's mind and almost made him faint.

"Endure it, my son," Bret sighed while using his insane strength to keep Khan still. "You aren't really burning. What you are feeling is the mana core flowing into your cerebrospinal fluid. Everything will be over soon."

Khan screamed in pain and punched the air. Bret had smartly placed him on a chair in the middle of the room, so he couldn't break anything during his struggles.

Khan couldn't even hope to escape Bret's grasp. His father had superhuman strength, something that Khan couldn't oppose.

"Almost done!" Bret said, and the scorching sensation that was filling Khan's mind slowly faded.

Khan began to calm down. Sweat had covered his body, but he ignored it and touched his nape as soon as Bret retracted his hand.

There was nothing unusual there. Khan only touched his nape. He couldn't even find a burn or a piece of missing hair.

"I'm still good after all these years," Bret exclaimed. "Those butchers in the army would have forced you to remain in bed for an entire week after the transplant. It must feel good to have a genius like me as your father."

"Do I need to ask you about tonight's food to make you stop bragging?" Khan asked, and Bret fell silent.

Khan handled the money and the food in the house. Bret had superior resistance to hunger and similar needs due to his enhancements, but he would have died anyway if his son didn't take care of his needs.

"I don't feel any different," Khan said after testing a few things.

His thoughts didn't move items. His eyes didn't suddenly gain the ability to see the currents of mana in the environment. He didn't even feel stronger than before.

"The mana core is only the trigger," Bret explained. "I told you that you need training."

Bret saw the disappointment in his son's expression, and determination filled his face. He decided that he would sacrifice himself a bit to make Khan happy.

"Close your eyes," Bret eventually said, and Khan followed his instruction. "Focus your attention on your nape. Imagine azure energy flowing toward your brain and the rest of your body. Visualize it with your imagination, and remain on that scene until you sense the same tremor you felt inside the mines."

Khan completed the exercise in an instant. When he focused on his neck, a tremor ran down his spine and gave him a vague idea of the foreign energy that now flowed through his body.

Khan turned to tell the joyous news, but he saw Bret crouching on the floor and coughing blood. Worry filled his mind, but his father reassured him immediately.

"Don't worry," Bret explained. "I broke a small oath by teaching you this visualization technique. I can endure it with my power. You should focus on visualizing the mana inside your body now. The next step consists in moving it according to your desires."

Bret coughed blood again after sharing that information, and Khan begged him to stop. However, a series of loud knocks suddenly resounded from the entrance and diverted their attention.

"I am Mark Highroot, first level warrior of the Global Army," The soldier on the other side of the door shouted. "Please, open the door, or I'll take it down."