Hajime Mogi is a character from the manga series Sanda by Paru Itagaki. He is a student and a friend to the protagonist, Kazushige Sanda. Mogi plays a supporting role, often providing commentary and insight into the events unfolding around him. His personality is portrayed as thoughtful and somewhat analytical, as he is seen offering theories about the behavior of other characters. For example, when the character Shiori Fuyumura acts aggressively, Mogi hypothesizes that her actions may stem from missing a friend, suggesting he is prone to psychological speculation rather than immediate alarm.

Mogi also demonstrates a keen interest in folklore and legends. He is shown to be fascinated by the mythology surrounding Santa Claus, a figure associated with December 25th, and he muses on the stories tied to that date. This curiosity contrasts with the indifference shown by his friend Sanda, highlighting that Mogi is more contemplative and drawn to the mysterious or magical elements within his world. His role in the story is largely defined by his relationship with the protagonist, serving as a confidant who helps to contextualize the strange occurrences at their school. No information is available regarding his background, family, specific motivations, notable abilities, or any character development he may undergo.