Ernst is a Royal Institute Researcher dedicated to supporting the protagonist's continent cultivation mission in Arcadia. He provides strategic recommendations for optimizing building placements to maximize happiness ratings across the realm.

Originating from an average planet, he comes from a commoner family where his father also worked as a researcher. Ernst has an older sister and both parents. Records list his age as 27 during the events of Trois, later noting 30. He stands 179cm tall and weighs 66kg. His birthday is December 30, making him a Capricorn with blood type A.

Serious and scholarly by nature, Ernst exhibits deep devotion to his work. His personal preferences include enjoying Othello as a hobby and favoring spirited women as partners. He appreciates citrus-based scents and relies on nutritional supplements for sustenance, while disliking foods requiring lengthy preparation times. He holds no particular affinity for specific animals.

Within cultivation operations, Ernst collaborates with fellow researchers Rosalia and Limoges. He specializes in advising structural adjustments to fortifications, enhancing collaborative efficiency between guardians. This expertise directly supports the protagonist's critical mission to stabilize Arcadia within its 115-day timeframe.