Trials
Inside the Dungeon of Trials, everyone has to go through a trial every 5 floors.
The difficulty of these trials increases as one clears more trials.
However, you can also choose the starting difficulty.
It goes like this…
[Normal] will give you 1X Difficulty in 1st Trial -> 1.5X Difficulty in 2nd Trial -> 2X Difficulty in 3rd Trial ->2.5X Difficulty in 4th Trial, and so on.
[Hard] directly jumps to 1.5X Difficulty in 1st Trial, then 3X Difficulty in 2nd Trial, 4.5X Difficulty in 3rd Trial, 6X Difficulty in 4th Trial, and so on for every trial.
[Expert] would be 2X Difficulty in the 1st Trial -> 4X Difficulty in the 2nd Trial -> 6X Difficulty in the 3rd Trial, and the difficulty will continue to increase in the same order.
Of course, these comparisons weren't accurate, but they were to give an estimation of how different each [Difficulty] is from the other.