Hello, lazur_koul, thank you for playing!
- For the Blue Tome, find an item called "Council's Invitation." You can get one by talking to the Prime Minister, Lady Marisa. Then go to Jyla's manor and speak to her maid, Vorosess.
- For the City of Mist, once you have 5 mask fragments, look at the glass door. The glass door can be found by going south from the Fast Travel point and into the stairs there. From there, you can fight the boss.