The concept of a Reality Marble (固有結界, Koyū Kekkai?, innate bounded field) is having one's inner world materialized and projected onto reality following the World Egg (世界卵, Sekai Tamago?) theory. Generally, it is used to refer to the alien common sense of demons (悪魔の持つ異界常識, akuma no motsu ikai joushiki?) and that it is how imaginary demons perceive reality and how a Reality Marble itself is their natural ability. But it is possible for humans to achieve this as an innate Bounded Field, though generally only in the cases of the powerful beings like The Twenty-seven Dead Apostle Ancestors and the greatest of magi who have spent years upon years researching. This ability is a similar and dissimilar method of "world creation" to Marble Phantasm, but rather than reshaping the world at their wil