The Trials of Judgement is a leather bound journal style book that has the approximate thickness of a fist. Corin first acquired this book in the landing room during his Judgement. The book was located on the third pedestal. Corin left a coin in exchange for it. While the Trials of Judgement originally appeared to be a blank book with no title, Corin later discovered that while he was in the Room of Valor writing had appeared on the pages. Corin uses it as a form of communication device to talk to a being who he initially names "Mysterious Book Entity". Trials of Judgement tells Corin that it is used by "The Voice of the Tower". It is later revealed that Corin had been communicating with his brother Tristan Cadence the whole time.
Trials of Judgement has runes inscribed on the inside of its spine that presumably have Tristan Cadence's mana signature.