James Charles is a supporting character in the series and is originally known as the final boss of the fictional otome game Regalia of Saints, Demons, and Maidens 2. He holds the title of a prince of the Grand Duchy of Mirchetta and serves as the diligent student council president of Mische Academy, the duchy's premier educational institution. His existence is defined by his hidden lineage, as he was born a half-demon under the birth name Ashtarte, a name given to him by his demon father. His human mother is the sister of the Grand Duke of Mirchetta, and she eloped with James's father roughly two decades before the story begins.

In his role within the story, James is initially wary and distrustful of strangers, including the protagonist Aileen when she arrives at the academy under a false identity. Despite his reserved and distant demeanor, he performs his presidential duties with a sincere and diligent nature. His motivations are deeply rooted in survival and personal peace. Unlike his fate in the original game, James has no desire to fully succumb to his demonic heritage or claim the title of Demon Lord. This is a direct consequence of the changes brought about by Aileen's actions earlier in the timeline, which prevented the tragedy that would have pushed him over the edge.

A key part of his background is the immense persecution he has faced. The powerful church within the duchy, secretly funded by his own great-uncle who feared James might be chosen as the next Duke, has targeted him with numerous assassination attempts. This campaign of terror forced James to grow up isolated and without friends, a lonely childhood that contrasts sharply with other characters who had companions. He eventually abandons his birth name, Ashtarte, in an effort to distance himself from his demonic origins, though he is later forced to confront this side of himself.

Throughout the narrative, his key relationships often begin with distrust, particularly with newcomers like Aileen, who he suspects is not who she claims to be. However, his path intertwines with hers as the plot to uncover the culprit behind a series of demon attacks in Mirchetta unfolds. In a significant deviation from the original game’s events, James transforms into his demon form much earlier than expected. The protagonist, Aileen, chooses to let him escape with the belief that he can still revert to his human state, an act that alters his predetermined tragic fate. His development thus centers on being pulled back from the brink of becoming a full-fledged demon lord and finding a different path under the tutelage of Rudolph Lauren D'Autriche, serving as a knight to Aileen Lauren d'Autriche. Information regarding notable supernatural abilities beyond his demon transformation is not detailed in available sources.