Jean Grey, also known as Phoenix, is a central character in the X-Men series. She is a mutant with powerful telepathic and telekinetic abilities, making her one of the most formidable members of the X-Men. Her character is complex, often struggling with the immense power she wields, especially when she becomes the host for the Phoenix Force, an immensely powerful cosmic entity. As Phoenix, Jean's abilities are amplified to god-like levels, leading to significant challenges for her and her allies in the series.