Magic

“Everyone has mana, Alexander. Even little Constans here has a core of mana inside her, and as she continues to grow, it will become bigger and fuller of mana, which, if she ever levels a magical class or magical skills, will be what she uses to power those skills.

Everyone’s core of magic is different.

Some people are born with more base mana or a higher mana recharge rate, similar to how a person is born with better hand-eye coordination or more muscles. But it’s not that you merely have a small core of mana, which is actually very common for many people without classes.

You have no core at all.

No mana.

No potential to magic, ever.”

- Momma Lena, Chapter 8 of Book 1

After analyzing the bodies of some men he killed, Alexander found out ‘cores’ and ‘orbs’ were essentially the same thing. The people of this new world also had secondary systems of veins that connected to the core Alexander lacked, hinting at cores being an evolutionary trait the people of this world had developed.