Edited by Jun Takahashi, Katsuhide Morimoto and Tetsuya Nagato, Undercover is offering a book called "Underman: The Empty World." Here is the text from the back cover.
The Solider of Love and Sorrow, UNDERMAN
The year is 20XX. The world, in which the souls of the people have been incapacitated by the forces of evil, is empty. Underman is born to restore these lost souls. The battle against sorrow wages on.
Beyond the about quote we don't have any firm information on the interior contents (if any,) but the physical book looks nice, leather cover and all.
More images follow after the click.