Adventures of Ugo

History
The Adventures of Ugo is one of the books donated by William Minerva with a hidden message on its ex libris.

Upon closer inspection, Emma discovers that the dashes actually form Morse code messages. One particular book, "The Adventures of Ugo," has the morse code for 'promise.'

This book portrays the fantastical adventures of a young man Ugo and his lemur friend, Marvine, which depicts a fantasy-like world parallel to what the orphans experienced during their escape from Grace Field House in the Demon World. William Minerva intended for the escaped children to use the book as a guide book on how to avoid the hazards outside Grace Field House and how to survive in the Demon World.

The Snakes of Alvar Pena refers to the Bloodsucker Trees. The book also hints at how to find the pen cap for the Promised Pen. During a pre-recorded phone call from Minerva inside the floating cabin which contains the elevator at Goldy Pond, he told the escapees that he left "the rest of the details" in "Marvine's bed". In the book, Marvine sleeps inside of a desk drawer, alluding that the pen cap was hidden in a nearby desk drawer.

Trivia

 * If you rearrange the spelling of "Marvine", you get "Minerva".
 * Yugo's name is a reference to the book's main character, Ugo, as Shirai originally planned for Yugo and his team to escape from Glory Bell using the book.