Three hours later, Mariel was lying helpless on the ground—too exhausted to move, and his breath had completely spent.
"Good work," Lukhiel said, stopping four steps to Mariel's left. "Your stamina has improved significantly. For a normal human, you're already quite fast. You're strong enough to take on a group of ordinary humans."
"I don't even feel happy about that compliment, Master."
It was impossible for Mariel to feel any satisfaction after being rendered so powerless. He was far too weak. He couldn't imagine what the world would be like if humans couldn't use prana. Perhaps the world would already be in the hands of demons, with humans kept as livestock. The thought was truly horrifying.
But if all demons were like his master...
"Still, since it's a compliment from a Primordial Demon like you, Master, I guess I should feel honored."
"Let me explain again—I'm not as strong as I was three hundred years ago. At this point, I'm probably the weakest Primordial Demon. Don't use me as your benchmark for power. But let's set that aside for now. As I said earlier, after you've rested, I'll teach you how to use prana."
"I'll keep that in mind. And, Master, I am resting right now. Did you come to tell me my rest time is over?"
"Oh! I'd love to say that, but no. I just come to tell you about prana; you can listen while lying there like that."
"Good. I was just thinking of kicking your butt when you fall asleep later."
"Ha-ha-ha. Do that, and you'll wake up hanging over a pit of crocodiles. Now listen carefully."
Lukhiel paused and sat down.
"All living beings with souls possess prana," the demon began. "Prana is the combination of physical energy and spiritual energy. If you run out of prana, your body will weaken, and in the worst-case scenario, you can die."
"Although all living beings with souls have prana," Lukhiel continued, "not everyone can use it. There's something called the 'power gate' that locks prana inside the body. It's said this gate exists because of the presence of spirits. That's why prana is essential for syncing with a spirit. And to use prana, one must unlock this gate."
"What about demons?" Mariel asked, recalling the books about spirits he had read. "Demons don't have spirits within them. Does that mean you can use prana from the start, Master?"
"Good question," praised Lukhiel. "And as you suspected, demons can use prana from the start. Demons don't have spirits, but that fact is actually a bit misleading. You already know that demons are born from human souls that enter the underworld. What you need to understand is that the spirit accompanying that soul merges into it, and thus, a demon is born. At least, that's my opinion. My power represents the spirit I once had as a human."
"…That's why demons are strong without needing to train."
"Exactly. But let's get back to the topic."
Mariel nodded.
"Once the 'power gate' is unlocked, prana will flow throughout the body, following the circulatory system. Because of that, the heart is the only organ that can't be regenerated. With prana flowing through the body, your physical strength will increase rapidly. If you train hard enough, running as fast as the wind won't be impossible."
Mariel immediately sat up upon hearing this. He turned to face Lukhiel, his face clearly showing his overwhelming enthusiasm, like a child in front of their favorite toy. But that wasn't surprising. Becoming strong was the first thing Mariel needed to focus on.
"There are many uses for prana," Lukhiel continued. "But for now, let's focus on those not related to spirits."
Mariel nodded, not at all opposed to it. He had already understood his master's method. Lukhiel trained him in three stages: physical, prana, and spirit. He had focused on physical training for almost three years. Now Lukhiel wanted him to focus on prana. Maybe in two to four years, he would be directed to use the spirit power within him.
"Prana can be used to walk on water and other liquid surfaces. Ninjas from the Eastern Continent use prana to walk on ceilings. They also have something called ninjutsu and ninja art. On the Southern Continent, prana is used as magic energy. On the Northern Continent, prana is used in a different way. However, out of all of these, I'd say no one applies prana better than the ninjas."
"In this continent," Lukhiel continued, "fighters focus on converting prana into specific elements. One can create and control fire, water, earth, lightning, and even wind with prana. However, one can usually only create one element. Once someone can create water, creating other elements becomes as difficult as mixing water and oil. This difficulty haunts both ninjas and sorcerers, and demons as well."
"You said 'usually,' which means there are exceptions?"
"Have you ever encountered the name 'Merlin' in any of the books you've read?"
"Merlin... the one who helped King Arthur establish Camelot?"
Lukhiel nodded. "Merlin is the only person who can do everything with prana. She can create all elements. She can create ice, lava, and even control the weather. She is older than even the oldest demons. Maybe she can answer your questions about gods. However, after King Arthur died at the hands of Modred, Merlin vanished. To this day, there's no trace of him."
"Ah," Lukhiel continued. "On an island that I don't even know the location of, there's something called the Tower of Babel. Some sorcerers believe Merlin is there. But no one has ever been able to prove it. Because of that, people believe Merlin is dead. But I wouldn't be surprised if she's still alive. When it comes to Merlin, nothing is truly impossible."
"Now, let's go back to the original topic," Lukhiel continued before Mariel could respond to his explanation. "Fighters on this continent focus on converting prana into the five basic elements. Lightning is the rarest element, and fire is the most common. My element is wind. You also need to consider which element you'll choose."
Lightning was the most destructive element. It could destroy anything it struck. Weak lightning could be neutralized by earth, but strong lightning destroyed everything. If Mariel wanted to focus on destructive power, he would need to choose lightning as his element.
Fire was… fire. Mariel didn't need to think much about this element. He knew exactly how dangerous fire could be. What was clear was that he wouldn't choose this element. Using fire posed a high risk of damaging the environment, and it would also be troublesome if he found himself in a situation where stealth was required.
Earth was very useful in many ways, but this element lacked flexibility. Mariel wanted to be a fighter who relied on speed; the earth element wasn't suited for him.
The same applied to the water element.
Lightning or wind. Mariel couldn't choose anything other than one of these two.
That was the conclusion Mariel had come to regarding the element he should choose.
"But before we get there, first, we'll open your 'power gate.' Are you ready, or do you need more time to rest?"
Ah, that was true. Thinking about which element to use was useless if he couldn't even use prana. First, he needed to make sure his "power gate" was open.
"I'm ready, Master," Mariel was prepared.
"Good. Then I'll give you two choices: do you want the easy way or the hard way?" Lukhiel asked bluntly, a sinister smile spreading across the demon's face.
Mariel swallowed his saliva. Lukhiel was a demon; he wouldn't forget that fact. What was easy for him could be difficult for Mariel, and what was difficult for Lukhiel could be easy for him. But it was also possible that easy would really be easy and hard would really be hard.
"You won't explain until I choose?"
"Of course not. It wouldn't be any fun if I tell you."
Mariel wiped the sweat from his temples and took a deep breath. "The easy way," he answered, deciding to choose the normal option.
"Then stand up. I'll hit you so hard that your heart will stop for a moment, then I'll fill your heart with my prana. In an instant, you'll be able to use prana."
"Wh-What about the hard way?"
"You'll just need to meditate until you can feel the presence of the 'power gate' inside you. The difficult part of this process is the long time it takes. It's possible you won't feel it until half a year later."
Mariel couldn't say he'd made the right choice, but he also couldn't say his choice was wrong.
"Now, stand up and prepare yourself for the overwhelming pain."
…Um, maybe he should have chosen the hard way?