So how does this magic work? How about asking her again to show it to me but slowly.…

            I asked Lilith, "May you show me how to properly cast a spell and with slowly?"

            "What doth thou mean by softly? (What do you mean by slowly?)" Answered Lilith with confusion.

            "Because you cast a spell in a matter of seconds, yet I want to see how this spell was created properly, so may you show me slowly?"

            Lilith nodded, understanding my request. She then began to stick out her hand in front of me and open her palm. After a few seconds, I could see a faint glow from around her hand and gathered on her palm. Yet I didn't hear any chanting from her. Is she not going to chant the spell?

            Is she trying to cast the spell without chanting or what? I could see all these faint glows had gathered around on her palm, and I assumed those faint glows were her mana. Even though it was gathered on her palm, somehow the glow was small, it was just a small dot. It was barely noticeable, but the glow made it noticeable. Immediately, Lilith chanted the spell "Pyr".

            All of a sudden, the dot of glow began to expand. I immediately focused on the dot of glow…Slowly, I could see something from outside the dot, sort of fuse into the dot, that made the dot bigger and brighter. It was as if the mana was absorbing energy from its surroundings, growing stronger with each passing moment until it formed the spell she wanted for it, a fire. The fire ignited without warning.

            So, I was wrong. The fusion isn't inside her body, the fusion is outside of her body. The dot of the beginning is her mana, we can assume that as the mass of a proton, and the outside energy is the mass of a neutron. As with the mass defect (Δm), Z⋅mp​+N⋅mn​−mnucleus​, we modify the Z⋅mp​ into mana A, and N⋅mn into mana B, and mnucleus​ into mana C. So it will be Mana A + Mana B→Mana C + Energy. The Mana C is the new mana that forms from the fuse of Mana A with Mana B, and the Energy is the release of energy from the fusion.

            Mana A is a mana from the caster, and Mana B is a mana from the environment. This makes sense because a lot of magic stories will tell about a special person who can do magic, and only they have a mana pool. There will be a question: why can't others or normal people cast a spell? The answer is that they don't have a mana pool like Mana A. What about Mana B? Well, Mana B surely will be there, because without Mana B, there will be no Mana A. Mana B can act as the source of mana or the raw material, that needs to be refined into the creature's body and become Mana A. So this magic thing uses two processes, refining in the creature's body to make Mana A, and the fusion to cast a spell.

            Okay, so we know the process of the fusion, yet we still don't know completely the entire process. How about the mana cost? Is there any connection between how long the spell is channelled into the energy? Or is the mana B a constant or variable for the mana A?

            Litih said, "Is that enough for thou? (Is that enough for you?)"

            I answered, "Well, sort off… Yet, there is something I need from you again…"

            "What? why? doth thou still want moe to grant me some explanation of how magic works? (What? Why? Do you still need more to give me some explanation of how magic works?)"

            Duh, yeah, of course, what I know is a hypothesis, I need some proof for the hypothesis. And, you are the demon lord, surely you are the first person who knows this thing more than anyone else. I answered, "Yeah…"

            "So what doth i want to try? (So what do I need to do?)"

            "As you can see, to do magic, there must be a cost, right?"

            "Thou mean mana cost? (You mean mana cost?)"

            "Yeah, so I need to see the different mana costs in the same spell…"

            "What doth thou mean by that? (What do you mean by that?)"

            "You just need to cast the same spell, like fire, yet use more mana into it, or use less mana into it…Will there be anything different from that?"

            "How much mana doth i want to use? (How much mana do I need to use?)"

            "How much mana did you use to cast the fire before?"

            "I barely used any mana to cast some few fire on mine palm, allow us see…. About 3-5 mana (I barely used any mana to cast a little fire on my palm, let's see….About 3-5 mana.)"

            "I see, how about you increase it, to 20 mana, and cast the same spell, fire…"

            "Alright then, doth i want to cast it softly like ere? (Alright then, do I need to cast it slowly like before?)"

            Well, I already knew the fusion, so, I told her, "You don't need to do that…"

            Lilith answered, "Alright then…" She started to stick out her hand and open her palm again. Immediately, she chanted the spell, "Pyr".

            The first thing I noticed was that the fire was bigger than the last fire. Yet I couldn't compare the differences between them. So I said to her, "You can put out the fire, and try to cast with 10 mana…"

            Quickly, she put out the fire and began to recast another fire. "Pyr" as she chanted it, and the fire appeared. I assumed with the difference of half her mana, the fire would decrease by half of the size. However, I was wrong. As I looked at the fire, the size was sort of 2/3 of the last fire, so it was only decreased 1/3, not half it. So what is happening here?

            I asked her to put out the fire and asked her to recast it again with 5 mana. As she understood and recast the spell again with the amount of mana I asked her, I was stunned by the fire she cast. The size of the fire was 3/4 of the fire before, so it just decreased by a quarter of the size fire before.

            If we assume 20 mana as the first comparison, the spell after that 10 mana and 5 mana should be proportional decrease with half it, so the 10 mana should be half of the size original 20 mana, and the 5 mana should be a quarter of size original 20 mana. Yet, the reality in front of me is different. Somehow the 10 mana decreased only just one-third of the original size, and the 5 mana decreased only just a quarter of the size 10 mana.

            So the mana B from the fusion must be constant, and mana A is variable depending on how much the mana is from the caster cast. It makes the mana B just a help for the fusion. Therefore, this mana B must have a limit, and the spell will be less effective as reaches its limit. Just imagine the limit is 100 mana, so the spell that costs more than 100 mana will be less effective, a spell that costs 200 mana will not increase 2x but just 1,5x, and 300 mana will increase just 1,25x until it reaches the peak of 400 mana, larger than 400 mana, there will be no increasing or effectiveness of the spell.

            Lilith suddenly said to me, "So? You know how the magic works?"

            I started to tell them about the concept of mana fusion, which was Mana A + Mana B→Mana C + Energy, and the limitation of Mana B because it came from the environment. As I finished the explanation towards them, immediately Varania asked me,

            "You mean the spell we created is a form of Mana C, and the size or effectiveness is a form of energy?"

            I answered, "Correct. Like the fire just Lilith cast, the fire is composed of a fusion of two mana and became one mana we called it mana C, yet the size and the brighter of the fire came from the energy of the fusion…"

            Lilith said, "What would befall would I reached the limitation of mana b? (What would happen if I reached the limitation of mana B?)"

            I answered, "The spell will be less effective…So this mana B can be more useful if you use a spell less than the limitation of the mana B, like the fire you just cast, even if you cast it with a different mana pool, yet the size is almost the same with another because the mana B."

            "So doth thou wot the reasonable shore of mana b? (So do you know the limit of mana B?)"

            "Well, I don't know the limitation of mana B, how much mana you can use to be effective…"

            Lilith smiled at me with dazzling eyes, and said "How about we test it, outside?"

            "Test it?"

            "To wot the limitation of mana b, so i want to cast a spell that cost moe mana, right? without is a better place than inside, because… (To know the limitation of mana B, so I need to cast a spell that cost more mana, right? Outside is a better place than inside, because…)"