King of Scars by Leigh Bardugo
It's related to the Shadow and Bone trilogy and the Six of crows biology.
Synopsis:
The dashing young king, Nikolai Lantsov, has always had a gift for the impossible. No one knows what he endured in his country's bloody civil war--and he intends to keep it that way. Now, as enemies gather at his weakened borders, Nikolai must find a way to refill Ravka's coffers, forge new alliances, and stop a rising threat to the once-great Grisha Army.
Yet with every day, dark magic within him grows stronger, threatening to destroy all he has built. With the help of a young monk and a legendary Grisha general, Nikolai will journey to the places in Ravka where the deepest magic survives to vanquish the terrible legacy inside him. He will risk everything to save his country and himself. But some secrets aren't meant to stay buried--and some wounds aren't meant to heal.
Yet with every day, dark magic within him grows stronger, threatening to destroy all he has built. With the help of a young monk and a legendary Grisha general, Nikolai will journey to the places in Ravka where the deepest magic survives to vanquish the terrible legacy inside him. He will risk everything to save his country and himself. But some secrets aren't meant to stay buried--and some wounds aren't meant to heal.
Recommendations:
This book is fantastic for fantasy and adventure lovers. It's part of the shadow and bone (the Grisha) story, with these books you will see the prince becoming the king of the Grisha country after the Grisha war.
Buy it on: Amazon.
Rule of Wolves by Leigh Bardugo
Synopsis:
The Demon King. As Fjerda's massive army prepares to invade, Nikolai Lantsov will summon every bit of his ingenuity and charm—and even the monster within—to win this fight. But a dark threat looms that cannot be defeated by a young king's gift for the impossible.
The Stormwitch. Zoya Nazyalensky has lost too much to war. She saw her mentor die and her worst enemy resurrected, and she refuses to bury another friend. Now duty demands she embrace her powers to become the weapon her country needs. No matter the cost.
The Queen of Mourning. Deep undercover, Nina Zednik risks discovery and death as she wages war on Fjerda from inside its capital. But her desire for revenge may cost her country its chance at freedom and Nina the chance to heal her grieving heart.
King. General. Spy. Together they must find a way to forge a future in the darkness. Or watch a nation fall.
The Stormwitch. Zoya Nazyalensky has lost too much to war. She saw her mentor die and her worst enemy resurrected, and she refuses to bury another friend. Now duty demands she embrace her powers to become the weapon her country needs. No matter the cost.
The Queen of Mourning. Deep undercover, Nina Zednik risks discovery and death as she wages war on Fjerda from inside its capital. But her desire for revenge may cost her country its chance at freedom and Nina the chance to heal her grieving heart.
King. General. Spy. Together they must find a way to forge a future in the darkness. Or watch a nation fall.