Haqua du Lot Herminium is a key character in the anime series 'Kami nomi zo Shiru Sekai' (The World God Only Knows). She is a demon from Hell who works as a spirit hunter tasked with capturing loose souls that escape to the human world. Haqua is a former classmate of Elsie, another spirit hunter, and is known for her intelligence and ambition. Despite her serious demeanor, she struggles with self-doubt and feelings of inadequacy. Her role in the series involves teaming up with the protagonist, Keima Katsuragi, to capture the loose souls and ultimately grow as a character through her interactions with others.