Diseum von Earlshide reigns as the current king of the Earlshide Kingdom. He possesses golden hair, a mustache, and emerald-green eyes, consistently adorned in high-quality attire radiating charisma and regal authority. Initially presented as a benevolent ruler dedicated to his kingdom's protection, a traumatic betrayal that nearly shattered Earlshide fundamentally reshaped Diseum. This event forged a more ruthless worldview, driving him to eliminate threats at any cost. He enacted sweeping aristocratic reforms compelling nobles to prioritize public welfare, significantly boosting productivity, tax revenues, and overall kingdom prosperity. His background includes attending the Advanced Magic Academy, where he participated in the first recorded devil subjugation. Merlin Wolford and Melinda Bowen rescued him during that conflict, establishing a lifelong bond. After graduating, Diseum temporarily abandoned his crown prince duties to travel as a vagabond with Merlin and Melinda, a period involving menial treatment from the duo. His fiancée Julia reportedly resented this decision. As king, Diseum focused on structural reforms, instituting semi-mandatory education for children under 15 to elevate literacy and numeracy. He reorganized the military into the Knight Order, Soldier Order, and Magic Division under a unified Military Affairs bureau. His foreign policy secured alliances with neighboring nations like the Swedes Kingdom. Magically, Diseum demonstrates above-average capabilities as an academy graduate, though some accounts controversially label his talents "legendary," suggesting reality-manipulating potential. He approaches threats with calculated strategy over brute force. Interpersonally, Diseum exhibits a relaxed, sociable demeanor, particularly with Shin Wolford. He insists Shin call him "Uncle Dis," treating him like a nephew, contrasting sharply with his political ruthlessness. His son August inherited both his traits and benevolent ideals. Diseum frequently consulted Merlin on governance matters, reflecting enduring trust despite their complex history. His character arc traces an evolution from idealistic prince to pragmatic ruler, constantly balancing personal connections against monarchical duties. Later developments involve him coordinating multinational efforts against demonic threats, leveraging alliances forged during his reign.