The First Sundering. The Crown of Endless Night, #1

For centuries, Kristoff, a stoic former knight, and his crew of immortals have endured a life that is less a gift and more a living tomb. Bound by a vengeful sorcerer's spell, they are tethered to the Crown of Endless Night-a sentient curse that traps its wearers in eternal suffering. They are never alone; they are relentlessly pursued by the Harbingers, shadowy beasts that are the physical manifestations of their own deepest traumas and regrets.
Exhausted and nearly broken, the crew finds a flicker of hope in an ancient prophecy discovered by the scholar Alaric. To shatter the crown, they must journey through long-lost realms hidden behind powerful magical seals. But as they cross the threshold of the first realm, they realize the curse is stronger than they imagined: the Harbingers are evolving, and every step toward freedom makes their own minds a more dangerous battlefield.