Liam Hamilton is the central protagonist of the story, a young boy who is actually a reincarnated middle-aged salaryman from modern Japan. He awakens in the body of the fifth son of the Hamilton family, a noble house that has fallen into deep debt and is on the verge of ruin. Because of a kingdom law that requires noble families to accomplish a noteworthy deed every three generations or lose their status, the Hamiltons are desperate. Liam, however, sees his new position as an opportunity rather than a burden. Freed from the responsibilities that weigh on his father and older brothers, he dedicates himself entirely to the study of magic, something he had always longed to do in his previous life.

Liam’s personality is pragmatic, analytical, and self-sufficient. He does not rely on his family for support, knowing they are too preoccupied with survival to help him. Instead, he uses his noble status to access magical education and ancient grimoires, teaching himself advanced spells and summoning techniques. He is calm under pressure and possesses a mature, level-headed outlook inherited from his past life. Despite his young age, he approaches problems with the patience and problem-solving mindset of an adult. He is also kind-hearted and caring, especially toward those who become his subjects or companions. He proactively improves the lives of people under his protection, relocating them to safer areas, providing food, and arranging for teachers.

Liam’s primary motivation is his genuine love for magic. He sees mastering it as both a personal passion and a practical way to secure a future for himself after his family inevitably loses their noble status. He initially plans to become an adventurer, but his growing power and the recognition it brings pull him into larger conflicts. As he gains strength, he becomes entangled in the secrets of the land, slowly rising in fame and eventually establishing his own territory in a monster-infested region, which he names the Promised Land. His role in the story evolves from a lone magic enthusiast to a ruler and king, with other kingdoms seeking either alliance or conquest.

Key relationships include his older brother Bruno, the fourth son, who informs him about the three-generation law and becomes one of his earliest supporters. Liam also forms close bonds with the various spirits he summons, such as the high spirit Jodi and the powerful fire spirit Radon, who become his familiars and trusted allies. Later, he encounters Princess Scarlet, a cursed girl who is not truly a princess but was used in a political scheme. Liam saves her, removes her curse, and invites her to live in the Promised Land, where she becomes his tenth familiar and learns magic. His family members—his father Count Hamilton and his apathetic brothers—initially ignore him but later come to rely on his abilities.

Liam undergoes significant development from a carefree child who only wanted to practice magic into a responsible leader who builds a nation and protects its inhabitants. He learns to balance his love for arcane study with the duties of governance, though he never loses his enthusiasm for discovering new spells.

Notable abilities include a high natural affinity for mana, allowing him to learn attribute magic (such as fire, water, earth, and wind) at an accelerated pace. He masters spirit summoning and contract magic, forming pacts with powerful entities. His skills also extend to curse removal and territory development. By the end of the first season, he has become one of the most powerful magic users in the world, capable of reshaping the environment and commanding formidable familiars. His signature approach is to solve problems—whether financial ruin, political threats, or magical challenges—by applying his ever-growing repertoire of spells.