The Two-Faced Ring is a magical object which has a profound impact upon the inhabitants of the Castle. The ring was originally a normal ring forged from gold through Alchemie, but Hotep-Ra imprisoned two Darke Wizards in the ring. An immensely powerful Darke artifact, the ring can only be removed from its wearer the Other way; as such, one must cut off the finger and remove it by sliding it down the bottom.
DomDaniel is wearing the Two-Faced Ring in this book.
DomDaniel is able to reform thanks to the power of the Ring.
Beetle and Jenna discover that, the ring is in the possession of Merrin Meredith, who uses it, along with The Darke Index, to create a Darke Domaine, in the palace eventually spreading throughout the entire Castle.
Marcellus Pye and Marcia Overstrand are preparing to destroy the ring, when the two wizards inside the ring escape and Consume Silas Heap's brothers, Edmund and Ernold Heap. At the end of the book, the Ring is destroyed for good, DeNatured by the power of Alchemical Fyre and turned to lead. However, with the presence of Saarn and Naarn expelled from the ring, Marcia had Marcellus transmute the ring once again from lead to gold, upon which it was given as a present to Jenna.
The Two-Faced Ring gives the wearer incremental Darke power, far greater than that which they would be able to manifest on their own. Merrin Meredith was able to use it to, among other things, create a Darke Domaine and a Darke Dragon.