Well as for the Cultivation Realm as well as the Levels in the Fantasy world and treasure ranks are as follows.
Treasure/Technique Ranks(Mortal, Earth, Sky, Heavenly, Immortal, Divine, God[Others will be mentioned later])
Fantasy World Levels(1-10 beginner(knight, wizard, barbarian, archer, magic swordsman, unknown[it can use any types of weapons as can learn any skills of every character], 11-20 intermediate, 21-30 high, 31-50 peak, 51-70 Royal, 71-90 Holy, 90-100 Divine and lastly 100+ God)
Cultivation Realm(Mortal)(Innate, External, Spirit Gathering, Earth, Sky, Heaven, Foundation Establishment, Innate Core, External Core, Spiritual Core, Golden Core, Mortal King, Mortal Sovereign, Mortal Venerable, Mortal Saint Mortal Emperor, Mortal Monarch and Mortal God) it's divided into low, middle, high, peak and supreme.
Immortal Realm and higher ones will be introduced later.
Advance Civilazations Levels are 1-9 and each level is divided into low, middle, high, peak.
John's power level is temporarily far apart than his peak.
His Fantasy world level for now is level 75 he can attain his previous level when he repaired his magic core.
Also his cultivation realm is Supreme Mortal God which is already the pinnacle of the mortal planes but his battle power is comparable to peak low level Immortals.
Also his knowledge is comparable to peak level 9 Advamce Civilization.