TV-Series
Description
Demetrio Earthwold is the First Prince of the Earthwold Empire and a significant figure in the light novel and anime series The Genius Prince's Guide to Raising a Nation Out of Debt. He makes his primary appearance starting in the fourth volume of the light novel series.

In terms of background, Demetrio is a young man whose primary claim to his position is being the eldest son of the imperial family. Physically, he is depicted as an adult male with gray eyes and gray hair that reaches his shoulders. His attire often includes a suit, cravat, and gloves, reflecting his formal and aristocratic standing. Despite his status as the first prince, he holds no particular advantage in the line of imperial succession beyond his birthright.

Personality-wise, Demetrio is characterized by a very strong sense of pride, which is not supported by his actual abilities. He is described as being incompetent and incapable of rational thought, a deficiency that drives his actions throughout the story. His most defining flaw is his deep-seated jealousy towards the series protagonist, Wein Salema Arbalest, the prince of the neighboring kingdom of Natra. Demetrio is envious that Wein, who is also an eldest son and prince, has earned substantial prestige both domestically and internationally, while he himself has not.

This jealousy forms the core of Demetrio's motivations. Unable to compete with Wein through intelligent statecraft or military leadership, he instead schemes to carry out what are described as completely meaningless acts of harassment against him. His actions are not driven by a grand political strategy but by petty resentment and a desire to undermine a rival he cannot best through legitimate means.

Demetrio's role in the story is primarily as an antagonist and political obstacle, particularly in matters concerning the larger Earthwold Empire. He is a representative of the old guard, as he is supported by the conservative factions of the empire, including influential nobles who prefer traditional power structures. His interests become directly entangled with the main plot during key political events. For instance, when the princess Lowa proposes a political marriage that would grant the kingdom of Natra immense power within the empire, Demetrio is forced to pay attention and agree to examine the matter, as it directly threatens his own position and influence.

Regarding key relationships, his most important dynamic is his hostile rivalry with Wein Salema Arbalest. He views Wein as a direct competitor and a source of personal humiliation. He is also naturally positioned against other members of the imperial family, like Princess Lowa, whose political maneuvering he views as a threat. His allies are drawn from the reactionary noble houses who wish to maintain their traditional influence in the face of newer, more competent leaders like Wein and Lowa.

In terms of development, Demetrio is a relatively static character who serves as a foil to the genius prince. He does not undergo a significant transformation or gain wisdom from his failures. Instead, his incompetence and irrationality are consistent traits that allow other characters, particularly the protagonist, to outmaneuver him. He is presented as an obstacle whose pride blinds him to reality, making him a useful tool for more cunning players in the political arena.

Demetrio possesses no notable abilities in statecraft, military command, or rational planning. His primary weakness is his inability to think clearly and his lack of strategic vision. His only source of strength comes not from his own talents but from the political and military support he receives from the conservative nobles who back him due to his position as first prince.