Haha, after so many hours, I, the author have finally come up with the perfect auxiliary chapter to ease your doubts.
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Cultivation Grades: These are the power of a cultivator based on the quality of their souls. From the tiny wisp to a large hell reality! Possibilities are endless!
Mortal Grade - Human Level. They are more powerful in the aspect of strength compared to humans, and are able to absorb the power of heaven and earth from the universe's core.
Mortal Grade is ranked 9th - 1st, and the higher your grade, the greater your soul fire is! A powerful Mortal Grade cultivator with a hell soul is able to crush a brick tower with his fists!
Heavenly Grade - Beyond mortal. They can live up to 200 years without losing their youth and are able to harness the power of heaven! Some are capable of using Soul Items less than Grade 4.
They are ranked 9th - 1st. The higher your grade, the greater you compatibility with the laws of heaven and earth. Strong Heavenly cultivators can summon a storm from heaven to devastate an army!
Celestial Grade - Gods... truly powerful cultivators who have transcended beyond the meagre human mind and become godly figures! No human cultivator had reached the Celestial Grade!
They are equally ranked 9th - 1st and are able to harness the power of the universe. Some own their own specific fragment worlds which grows as they get stronger.
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Realms, Dimensions, and Cores!
I shall update as the story progresses and the view over the entire plane grows.
Universe Core - This is the centre of the universe, holding about 80% of the universal natural energies like mana, Ki, and Qi! Cultivators tap from this core to get stronger, and are able to harness powers of their world!
Earth's Core - It holds no magic power, but is what keeps humanity from falling into the Abyssal Realm. The earth's core is extremely large, and is located at the hottest part of the planet.
Heaven Dimension - This is the perfect dimension for cultivators. It is overflowing with universal power, and helps cultivators cultivate their energy at twice the normal rate.
Hell Dimension - This is a dimension filled with chaos energy and is the worst place to cultivate energy. Unlike Hell Realm, Hell Dimension drops the quality of your soul, rendering your cultivation... useless.
Celestial Dimension - A quiet place with zero chaos energy and abundant order energy. It is the only dimension which has a direct gateway to Heaven Realm, just breathing in the air help you cultivate energy.
Heaven/Celestial Realm - Sleep for a day here as a Mortal Grade, and wake up as Heavenly Grade. Order energy is limitless, and even the fruits here are more powerful than a 3rd Grade Elixir! Everything here is at the Heavenly Grade... even the air!
Hell/Nether Realm - Home of demons and beasts. Chaos energy runs rampant like the wind here, with strange phenomenon like 20 metre long black lightning, 100 metre large cat and so on.
Abyssal Realm - Devouring realm. Home of the astral beasts and the largest realm in existence. An abyssal realm is endless, and any world without a core is pulled into it.
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That's all from the author now, will update more as the plane grows. Heh heh.