Each class contains extra 5 Levels compared to the previous class.
Levels 1 to 10 - Trainee / Apprentice / Classless
Levels 11 to 25 - 1st class ( D ranker )
Levels 26 to 45 - 2nd class ( C ranker )
Levels 46 to 70 - 3rd class ( B ranker )
Levels 71 to 100 - 4 th class ( A ranker )
More than Level 100 - Demigod Realm ( S ranker )
Class progression can only be done after completing specific quests.
After Reaching Demigod Realm there shall be no Classes, only Realms.
I will provide further details as the story progresses.😌