A "fatal flaw" in mythology refers to a character's tragic weakness or defect that leads to their downfall. This concept often underlines the theme of human imperfection, making the character relatable despite their extraordinary circumstances. The flaw can manifest in various forms, such as hubris, jealousy, or an inability to recognize one’s limitations. This aspect of character development serves to reinforce moral lessons, illustrating that even the mightiest heroes can be brought down by their own vulnerabilities, adding depth to the narrative and an exploration of human nature.