The game was unable to be made as completely as we initially planned to due to time constraints, so the south exit doesn’t lead anywhere, and the last 2 spells did not see any use (the last spell does do something by the way).
You can shoot fire to see through the darkness and read the bottom texts. The shape of the east room resembles the shape of a previous room and the texts hint to what to do in that previous room. You may not know what all the symbols mean, but you should recognize the ones that represent spells, and you can look for where the other symbols have appeared before to maybe get a sense of what the symbol means. I can’t really give more information without spoiling the solution, but it’s fine if you want to give up at this point since the last room is just empty and there’s no content after that.
Hopefully in a future version of the game we will be able to add more clues to help the player figure out what the symbols mean.