If you haven't heard already from someone, there is indeed a 16th Wings Of Fire book coming out, presumably to be released sometime halfway through 2026, though it is NOT confirmed. Tui has stated that she will be involving Umber in this book/arc along with some other NEW characters that Tui is currently working on their backstories. Another thing we know so far is that there will be a NEW ship, which involves the main protagonist for book 16! (Also my bet is that she's going to give Kinkajou a book of herself or at LEAST a POV in a prologue or epilogue, cuz she's Tui's favourite character AND she is the only dragon in the Jade Winglet without a POV book of her, along with Umber) BUT ANYWAYS, REMIX AND SPREAD THE WORD!! :D
