In this guide, I will share with you how to unlock the secret mirror library and obtain the luxurious chest in there.
The first book is obtained from Date’s challenge.
Tricolor File (Book 2 – Bathysmal)
Teleport to Dainichi Mikoshi north waypoint and head north. Make sure Enkannomiya is in Evernight.
Go into the bubble and you will get transported to the Vishap Research Lab.
Talk to the NPC to start the quest.
Open the gate with the Cryo monument and defeat the Bathysmal Vishap.
Investigate the item to complete the quest.
Antigonus (Book 3 – Before Sun and Moon)
Teleport to the waypoint and southwest of Dainichi Mikoshi and head northwest.
Talk to the two NPCs to start the quest.
Teleport to the Serpent’s head southwest waypoint and head north to find Antei.
Pick up the Ruin machine’s core and activate the rain guard.
Defeat the ruined guard and pick up the item.
Talk to Antei to complete the quest.
Puzzle (Book 4 – In the Light)
Teleport to Dainichi Mikoshi waypoint and head south.
Use a bow character to explode the barrel and tear down the wall.
Hit the triangular mechanism once.
Change the time to white night using the mechanism outside the room.
Head back into the room and hit the next triangular mechanism to move the wall.
Then, switch back the time to Evernight.
Enter the room again and activate the sigils on the wall.
Teleport to the Serpent’s Head northwest waypoint and head south.
Walk into the blue sigil wall according to the right order as shown on the wall earlier.
It is counted once there is a particle effect on the ground when you run through the wall (don’t need to bounce back to the middle).
Collect the common chest in the middle to obtain another puzzle book.
Yae Publishing House (Book 5 – The Serpent)
After collecting the treasure chest, head to Yae Publishing house in Inazuma city to buy the last book. The book is titled ‘The Serpent and Drakes of Tokoyokoku.’
Activating the mirror (Luxurious chest & achievement)
Teleport to the waypoint northeast of the Narrows and enter the library.
Talk to the NPC twice to start and end the quest.
Return the books to the bookshelves to unlock a secret mirror library.