Originally Posted by MeaK

"The higher the difficulty of the stage, the higher the chance of getting upgrade materials."

Uh-oh, MLG mode incoming?

I assume this is some kind of Hitsuji-like mechanic where the event girl needs unique materials to evolve instead of bloom dragons.

Kojako metioned that there are multiple maps, so guess it's just that the later maps give better rewards. Sort of like farming 11-1 or 12-5 for 80 Stamina Gardens.

More interesstingly is the note that you can use them on any character, so they can be interessting, even though you have done the Event Part.