Idk but

Class -1 (baseplate) level needed: 0, class 0 (grassland) level needed: 5, Class 1 (winterland) Level Needed: 50, Class 2 (cave) Level needed: 300, Class 3 (Deeper cave) Level needed: 1,000, Class 4 (Sky) Level needed: 5,000, Class 5 (The moon) level needed: 15,000, Class 6 (The mars) Level Needed: 50,000, Class 7 (volcano) level needed: 300,000, class 8 (crystal cave) level needed: 1,000,000, Class 9 (The Space) Level needed: 3,000,000 and so on...