"You may already know about it, it has been proven with magic by scholars. The air we're breathing is composed of different gazes" Arima said.

"Now, one of these gazes is the fuel with which fire burns naturally. From where I come from, it was called oxygen. And the more oxygen there is, the stronger the fire will be"

Arima created a projection, and numerous blue circles were depicted in it "Theses circles are oxygen" He said and then the representation of a fire appeared, while the fire burned the blue spheres were slowly going toward it to disappear soon after.

"So, if you want to raise the power of your fire magic, you can do that" The projection changed, this time, the blue spheres started gathering together in a single place, then a small flame ignited the all and created an explosion.

The students exclaimed like they understood something and noted it down.

"Of course, it's only in the case of natural fire. With magic, once you're around the fifth level, you can replace oxygen by mana. But in that case, it's just that oxygen was replaced by mana. So, this theory still works" Arima said

"Also, like most of the elements can be condensed, fire can be compressed to create destructive bombs, like this one" Arima waved his hand and red marble appeared in his hand. Everyone looked at him with confused eyes and the latter laughed.

"Would you believe me if I said that this marble has enough power to destroy at least everything in a hundred-meter radius?" He asked and every student directly screamed in their minds to never doubt anything that Arima would do anymore.

Arima smiled "Well, that was fire's practical use. As for its magic theory, it's another story. There's not really a specific theory for fire. Actually, it's also a very special element, it's after all, the bane of every other element. The magic theory of fire is simple, it's just burning" He explained

"That's what you call the fire theory, flames that can burn everything. Fire that consumes light, burns darkness, disperses wind, crumbles earth, evaporates water, destroys lightning. That's what the flames can do, turn everything to ashes. Fire can also purify, it can bring happiness and rest" Arima said.

"Fire can also give life and represent pa.s.sion" He then smiled "Fire has followed humanity since the beginning of times, of course its theory would be powerful" He declared and cleared the projection.

"Next will be water then" Arima announced and then his expression darkened a bit "…Now that I think about it, I think I'll need to talk about molecules" He muttered and Night tilted his head.

"Okay" Arima gathered his thoughts "There are two elements composing water, one being what I talked earlier, oxygen and the other being what we call hydrogen. When those two elements join together, they create molecules of water, which can't be seen with the naked eye. In the end, water is a congregation of these molecules" Arima explained with a frown on his face and when he finished he sighed.

"Do you understand?" He asked and all of the students nodded this time "Then it's fine. Next, as you all know water can take three different states, liquid, gaseous and solid. What I want you to learn in this lesson is that water doesn't really need a change of temperature to change form. At least with magic" He said and Isla's eyes widened in shock.

"What does that mean?" She asked. Her specialty rested on water magic, she always changed its state by thinking about the change of temperature.

"The explanation lies on the molecules. When water is heated, the molecules are agitated and start receding from each other. That's when the distance between each molecule is too big that the water is in gaseous state. When it's ice, when the temperature falls, the molecules approach each other, and their agitation slow down. So, you can define ice by the molecules that are stuck together or very close from each other" Arima explained and created projections explaining the two phenomena. He then looked at Isla.

"That's why it's better to think about the change of state based on the molecules, when you think about it as a change of temperature, more mana is needed and also, when you think about heating, you start thinking about fire, which impedes your actual water magic" He said and Isla looked back at him agape.

She stood up and directly left the room to test it out. Arima just looked at her and smiled "Well, let's continue with the magic theory of water. I'm sure Isla knows about it, so I will talk about it anyway"

"Well, to be honest, the three states of water can be used individually for magic theory. In liquid form, you can clean anything, drown anything. But let's be honest, the liquid form is better used with the first-degree application, with compression and pression, it's a very good destructive weapon"

"Then, what about its gaseous form? Well, there's no much use in the first degree. But with theory, you can make things like illusions and also good displacement magics. Mist can also be used as a detection magic, because it can spread everywhere in a very large volume"

"Then, we have ice. It's the strongest weapon of water magic users. They are sharp and solid, it can kill easily, as well as a blade. And even if it isn't needed to think about the temperature when you create it, it's still extremely cold and you can freeze anything with it. And the magic theory is not varied too, but it's the best kind on one aspect compared to the other elements. This aspect are seals. Eternal, cold and strong prisons"

Arima explained in one go the most important aspects of the three states of water.

"Let's continue, I'll talk about lightning magic now. First, let me tell you, lightning magic is my specialty, but my understanding of it is not really different from the others" Arima said and the students were very enthusiast. Arima was going to talk to them about his specialty.

"In a natural situation, lightning is produced by a particular phenomenon. Now let me explain something, the simplest I can. In our world, there is particles called electrons and protons. They are both charged negatively and positively respectively. Electricity is usually produced by a flow of electrons only. Basically, when electrons move from one place to another, they produce electricity. Remember that"

"Now, back on lightning. It's a discharge generated between electrically charged regions. So, between two clouds in a thunderstorm, for example. But it also can be between the ground and the clouds, and in one cloud alone. I'll show you an example" Arima said and stood up.

He extended his hands and in each of them, some electricity appeared. Arima brought his hands close to each other. When they were around half a meter close, some sparks started appearing between. And suddenly, a thick lightning connected the two along with the sound of thunder.

"Ah!" The students shouted and covered their ears. When they looked back at Arima, the latter was already sitting on the desk, observing them with a smile. At that moment, they all felt very embarra.s.sed.

Arima laughed lightly and created a projection, showing three situations, lightning between clouds, in clouds, and toward the ground "I won't explain you how the clouds are charged, because it's a bit more complicated and need a lot of details. Just remember that lightning is produced by two charged regions, 'interacting' with each other" He said.

"Also remember that lightning magic isn't all about lightning but also electricity. The former is for destruction and the latter is a bit more delicate, if I can say so. So, let's follow with the first-degree application" He declared and smiled.

"There's not much to say actually. Lightning is the most destructive elements, even surpa.s.sing fire and light. And it's also very fast. With electricity, you can do a lot of things, electrocute, create physical weapons and platforms, you can also create things like electric familiars"

"Lightning is a very versatile magic, almost perfect in defense, attack and speed all together. It also has no particular weakness when facing other elements. Now, what about magic theory? It's a bit like fire. As long as you give a good image and theory, lightning can burn and electrocute everything. It's also true that lightning is even older than fire in history. It is said that humans learned how to use fire thanks to lightning. There are also numerous legends about lightning divinities"

"These divinities were also frequently depicted as the king or the ruler of G.o.ds, like Zeus, for example, King of Olympus. Ultimately, giving a lot of power to lightning's magic theory"

Arima said and checked the time "Let's finish this period with Spirit magic, because it's a very special element. Only pertaining to the world of magic, meaning that spirit magic doesn't have any scientific explanation"

"Each matter in the universe produce spirits, fire generate fire spirits, water create water spirits and so on. Spirit magic basically allows the user to use every spirit around them for their own use. That's why Spirit magic users really possess the best versatility in all the magic world. But in exchange to that, the magic theory cannot be used. The only theory you can use with spirits is infusing, directing spirits into a weapon or an armor to reinforce them to a very high level"

"And it may sound like an ineffective magic, but it's actually really terrifying when you use it correctly" Arima finished by saying that and stood up.

"That's it for today, come back tomorrow" He said and directly left the academy along with Night and Lanya. The next to leave was Arister, he shrugged after Arima left and also teleported away.

That day, one more time, people heard of the things Arima taught about, even renowned scholars were really enlightened by Arima's words.

The evening of that day, our trio was eating at the Inn with Arister "You, aren't you stronger than before?" The latter asked while they were eating.

Arima smiled at him "Yeah, things happened. It was unexpected, even for me" He answered.

"Unexpected…" Arister smiled wryly "If I'm not wrong, you went up by around two skies already. What kind of unexpected is that?"

This time it was Night who laughed "You're right, but this guy is the definition of unexpected. So, if even him says that something was unexpected, then just take it as miracle" He said

Arister sighed and shook his head "At that point, can't you already beat that Earthen G.o.d alone?" He asked and resumed his dinner.

"Well" Arima pondered for a moment "Maybe I can if I resonate and use the 'One thousand parade' along with my undead form. Maybe I won't even need to use the Omni form" And then said.

Arister looked blankly at him "Sorry, I can't understand a thing of what you're saying" He commented and Lanya chuckled.

"Yes, I can beat him already" Arima summarized with a wry smile.

"Well, that's good for you" Arister followed "I think that I can breakthrough the second sky soon too" He then said and looked at Arima "Your lessons are really more useful than I thought"

"Oh" Arima smiled "So you learned something?"

"Well, who wouldn't, when they listen to that. My main magic is darkness and maybe as you said, it's possible that I am on the evil path" He wryly told "Your explanation about darkness, although it was short, it really was instructive. Thanks for that"

"There's no problem" Arima responded

"Well, your lecture about the limit break was maybe the most useful one actually. It's really a good technique to give a killing blow" Arister said.

"It's true, I admit that it's really useful. Well there's also the soul contract, but for you it's useless since you have the inheritance of Ares" Arima responded "By the way, how does your inheritance materialize? Ares is a G.o.d of war, right?" He asked.

"Ah" Arister smiled "Do you want to see?"