There are four red crystal flowers in the challenge floor area that Raidy protects at first. You don't have to enter one of the raid areas to get to them. They aren't drops from enemies, but flowers that you can find in the area, and have to interact with to get their crystals.
I'd love to translate the game to other languages later, but since that would require to manually change every message box, and that I'd have to update new content in several different game versions, it's not something I plan to do for now. When the game is done, or nearly done, more languages is certainly an option to add to the game.