On December 12, 2018, Nintendo released a Feh Channel video revealing details on Book 3. Details include the following:
Spooky New Location
The "Realm of the Dead"
- First Mythic Hero: Eir
New Hero Fest
- Lewyn, Owain, Eir, and Ophelia
First Summon Ticket
- Tickets will be awarded for a free "start" to a summoning session.
- Rewarded from Forging Bonds
- Tibarn: Lord of the Air revealed, to be added at a later date
- Nailah also seen in preview
Free 5* Hero: Eir
Free after completing Book 3 Chapter 1