https://store.steampowered.com/app/1350660/ARIA_CHRONICLE__Digital_Artbook/

This DLC contains the “Digital Art Book” of the Aria Chronicle.
The file is provided in PDF format,
and is translated into Korean, Japanese, English, and Simplified and Traditional Chinese.

The “Digital Art Book” contains the development story and description of characters,
which can spoil the game. Please come back after playing the game for the best experience.

The “Digital Art Book” contains the following:
■ Characters
■ Heroes
■ Costumes of Aria
■ Dungeons
■ Monsters
■ Items
■ Fan Art

The “Digital Art Book” consists of 87 pages in total.