In the midst of his fight with Lanya, Night suddenly coughed blood although he hadn't suffered any external injury. His eyes widened and he drew a red rune with his left hand. He flapped his wings and swung Karma at the rune. A powerful explosion knocked both him and Lanya back.

"I see…” The dragon smiled. “So, you were using gammas since the beginning, huh? That's impressive. Not only didn't I notice it at all, but it’s also quite a feat to have applied that theory just after learning it. But, it's an easy thing to heal. Next time you should take your time to predict the moment where I will be the most perturbed by it."

"Well," Night exhaled and landed on the ground. "That should be enough for today. I taught you all of the fifth arts. Arima and Arister should also have finished," he uttered and looked up. The two people in question appeared in midair.

"Hey, hurry up. I didn't use time magic to create this one and I want to sleep," Arima spoke and left the dimension. "You have three minutes before I severe the link to this place," his voice transmitted one last message even after he had left.

Night shrugged and changed form before jumping on Lanya's shoulder. "Let's go," he said and the three people remaining followed after Arima.

***

The next day, Arima resumed his lectures as planned. "We're left with wind and earth, right?"

"Let's go with wind first. It's the most complicated before earth. Wind is the flow of gases in the atmosphere and its movements are produced by variations of the atmospheric pressure. That pressure is basically the weight of the air around the planet. Since it's never even, there's always winds and sometimes hurricanes."

"Let me give you an image," Arima waved his hand and the hologram depicted an uncomplicated parcel of water. "Imagine a calm water tank like this one and an object falling in the center."

On the hologram, a white square fell in the water. "When it falls, it'll create a pressure on the surface and generate waves that will flow outward. It's the same principle with the wind, just that the object is atmospheric pressure."

"The water is the air itself, and the waves are the wind. Many things can disrupt atmospheric pressure, but the main actor is us, humans. We make buildings that deviate the wind, cast magics that disrupt air, and just simply breath along with all of the living beings on this planet.”

“Let's talk about tornados for a bit now. How are they formed? Usually, it's after a thunderstorm which creates a cumulonimbus cloud and disturbs the flow of wind. It will create a horizontal swirl that will suck up warm air from the ground, creating another disturbance and causing the swirl to be vertical, thus, creating a tornado. Well, this is a really summarized explanation while skipping many details."

"There's also a lot of different conditions that are to consider in particular cases. But remember this at least, instability in the flow of wind can be created by the clash between cold and warm air. The main reason is that they don’t really mix together and ‘push’ each other."

"The last thing I want to talk about is the composition of air. As I said before, the air is composed of different gases. First, there should be nitrogen, which is in the largest quantity. After that, we have oxygen, necessary for humans to live. Then there’s argon and lot of other gazes in really low quantity and density.”

“But an important thing to know is that the air has always around 0.4% of water vapor; 1% above the sea level. As a wind mage, if you can separate those gases you can create poisonous air, by either getting rid of oxygen or nitrogen, because even if the former allows us to breathe, if we take it in alone, it becomes poisonous to some extent. Although it would be quite hard to kill someone with it."

"You can isolate water and condense it. You can also make your wind cold or warm depending on how you control the molecules."

"Now, let's continue with the application. Of course, wind can be used as blades and shields. It shares some similarities with water on that aspect. You’re able to make destructive winds such as tornadoes. You can control the composition of air, the ambient temperature, and the wind strength to impede your opponent."

"As for the magic theory…" Arima mused. "Well, to be honest with you, it has not much presence compared to the other elements," he said and looked at Lena.

"But it isn't like there's nothing you can do with it. I may be unable to find good ones, but if wind is your specialty, you can give it some thought. There's a lot of things to use for that; legends and mythology are just a part of them."

"Well, the last one is earth, right?" Arima smiled and asked the obvious question. His students nodded and he pondered for a few seconds.

"First of all, let me tell you this. Planets are separated into four central separate key layers. The crust, the mantle, the outer core, and the inner core. For the core areas, I'll let you imagine what is inside. It’s basically very hot. I'll just talk about the mantle and the crust today. The combination of the crust and the upper mantle, representing the surface of our planet, is called lithosphere. What I want to talk about are the tectonic plates, that are like large pieces of the lithosphere."

As always, an hologram appeared to back up his explanation.

"In theory, tectonic plates float and travel independently over the mantle and it's at their boundaries that seismic activity comes from. If I'm not wrong, and it's just an assumption based on my inspection, but there should be around forty plates on this planet. Of course, there's a reason why I'm telling you this, earth magic users need to at least understand the ground on which they are standing."

"Which leads us to the composition of what we commonly call earth or the soil. It consists of around 45% minerals, 5% organic matter, 25% water, and 25% of air. These are the main components of soil, which are also needed for life to grow on it. Such as trees, flowers, fruits, and grass.”

“But still, remember that soil only denotes the surface of the planet. The majority of the planet is just rock and is, of course, the main strength of earth mages. On this planet, there's a lot of minerals that compose what we call the mantle. There're incalculable quantities of things like iron, aluminum, silicon, potassium, magnesium, and oxygen again."

Arima inhaled. "Let's go, last explanation for the eight elements. For a first-degree application; earthquakes, crevasses, landslides, rock manipulation, and metal control. You could say it’s a magic that allows attacks that carry a lot of ‘impact’. It's also one of the best when it comes to pure defense. Especially with an elemental body."

"As for the theory, there's a very important one; gravity."

"Eh?" After Arima's declaration, the class exclaimed in bewilderment. Arister wasn’t an exception and didn’t know what correlation there was between earth and gravity.

"I know that mages think that the only way to increase gravity somehow is to use wind to intensify atmospheric pressure or neutral magic to directly push the opponent toward the ground. Some also try to use space magic. But gravity comes from this," Arima pointed toward the ground and said.

The students followed his finger and looked at the ground baffled. "Of course, it's not the ground that is generating gravity, it's the planet itself. The explanation behind this lies in space-time theory so I won’t speak of it for now. Anyhow, as a matter of fact, earth magic has a direct connection to it so you can control gravity with its magic theory."

"Let me show you," he closed his eyes and slowly opened them, they were already glowing because of his sigil. When the students realized that Arima had cast a magic, they felt slight shaking at their feet and they were suddenly pressured by a strange force. They had to give their best to not fall under the pressure. Around the entire room, the sound of the chairs cracking was resounding.

"This is triple gravity," while his students were struggling, Arima casually said. He then closed his eyes one more time and the pressure vanished. At the same time, the chairs were repaired. Everyone sighed in relief and looked at Arima.

The latter smiled at them. "Well, you felt it, right? It wasn't neutral, space, or wind magic, but it indeed was mana imbued with the earth affinity," he declared and the students silently listened.

"Let me show you something else," Arima raised his palm and a blue transparent cube formed above it, at the same time, his sigil revolved.

"[Cavum Nigrum]," he chanted and a black disc appeared in the cube. It looked like a spiral of darkness with a pitch-black center.

"This a black hole," Arima grinned and said as he exhibited the cube by making it hovering around the classroom. "It's a gravitational field so strong that it even traps radiations. Nothing can exist in a black hole, no matter, no light. It's generally formed when a star dies and closes on itself, creating a zone of inescapable gravity. Once again, the cause is something I will explain once I start talking about space and time magic."

"Now, do you understand?" Arima observed his students and grinned. "This small black hole is currently contained in a spatial cube I created. Do you know what could happen if I dispelled this cube?" He asked and his students slowly shook their heads as an ominous feeling invaded their minds.

Only Ofia and Arister paled when they heard that. If they understood correctly, that thing was more than dangerous. In contrast, Lanya was as casual as always.

Arima smirked. "If I release it, even as small as it is, it would demolish at least half of this continent and maybe suck every last bit of air present on this planet. Only people at the eighth level or higher would be able to survive."

The students' minds froze. A few seconds later they all gathered in a corner of the room, as far as possible from that cube.

Arima laughed at the sight. He pointed his hand at the cube and clenched it into a fist. The spatial cube glowed and gradually suppressed the black hole until it disappeared. Everyone sighed in relief.

"Of course, I advise you to not try this magic unless you're able to lock space with magic… and unless you want to die because of your own magic and kill millions, and maybe billions, at the same time. Well, not that you would be able to it though."

Arima smiled then stood up. He headed toward the door of the class with his students' eyes following his every movement. "It's the end about basic elements. From today onward, for three days, I'll answer any advanced question you could have. After that, I'll enter in the non-elemental topics."

He instructed and left with Lanya and Night.

***

In a strange and huge garden, which now had a gloomy atmosphere filling it, Lilis touched the image projected on the water and a deep voice resounded around her ears and in her mind at the same time.

"|| User: Lilis Zesta, Goddess of Worldly Emotions. ||"

"|| Key Granted: Azes Kaeles, God of Order. ||"

"|| Target of The Rewind: Arimane R. Blade. Current status: Kind Demon, Death Hunter, Silver Emperor. ||"

"Arimane… R?" Lilis muttered. She had never heard Arima talk about a middle-name. "And Silver Emperor? He actually became one since the last time I saw him?"

"|| Target’s Verdict: Lawless Offender. ||"

Lilis thoughts were interrupted.

"|| Target's Threat: Highly Dangerous. ||"

"|| Target's Past: Recorded. ||"

"|| Target's Future: ... ||"

"Mh?" Lilis was confused. “Why did it stop?”

Although the Time Garden only showed the past of an individual, it could vaguely predict the future to understand the target better. This garden was a place which even the High Gods didn’t know the operation behind. It was supposedly something left by the Original God.

"|| Target's Future: … ||"

The voice repeated its words.

"|| Expected to Become a Plane Guardian… Wrong . . . Conflicting Information Detected. God, Killer, Demon, Faker, Eternal… Error. Failure. Impossible to Determine Target’s Future. Proceeding. ||"

Lilis was mystified. She already didn't know what a Plane Guardian was at all and on top of that, the Garden started malfunctioning. She didn’t even how she should react.

"|| Rewind Acknowledged. Initiating. ||"