The Farseer Trilogy by Robin Hobb
The 3-book set of mass market paperback novels includes the below titles:
Assassin’s Apprentice (ISBN 9780553573398): Young Fitz is the bastard son of the noble Prince Chivalry, raised in the shadow of the royal court by his father’s gruff stableman. He is treated as an outcast by all the royalty except the devious King Shrewd, who has him secretly tutored in the arts of the assassin. For in Fitz’s blood runs the magic Skill—and the darker knowledge of a child raised with the stable hounds and rejected by his family.
As barbarous raiders ravage the coasts, Fitz is growing to manhood. Soon he will face his first dangerous, soul-shattering mission. And though some regard him as a threat to the throne, he may just be the key to the survival of the kingdom.
Royal Assassin (ISBN 9780553573411): Fitz has survived his first hazardous mission as king’s assassin, but is left little more than a cripple. Battered and bitter, he vows to abandon his oath to King Shrewd, remaining in the distant mountains. But love and events of terrible urgency draw him back to the court at Buckkeep, and into the deadly intrigues of the royal family.
Renewing their vicious attacks on the coast, the Red-Ship Raiders leave burned-out villages and demented victims in their wake. The kingdom is also under assault from within, as treachery threatens the throne of the ailing king. In this time of great danger, the fate of the kingdom may rest in Fitz’s hands—and his role in its salvation may require the ultimate sacrifice.
Assassin’s Quest (ISBN 9780553565690): King Shrewd is dead at the hands of his son Regal. As is Fitz—or so his enemies and friends believe. But with the help of his allies and his beast magic, he emerges from the grave, deeply scarred in body and soul. The kingdom also teeters toward ruin: Regal has plundered and abandoned the capital, while the rightful heir, Prince Verity, is lost to his mad quest—perhaps to death. Only Verity’s return—or the heir his princess carries—can save the Six Duchies.
But Fitz will not wait. Driven by loss and bitter memories, he undertakes a quest: to kill Regal. The journey casts him into deep waters, as he discovers wild currents of magic within him—currents that will either drown him or make him something more than he was.