The DARK PHOENIX SAGA is an extended X-Men storyline from Marvel Comics running through X-MEN  #129-138 (1980) from the creative duo of Chris Claremont and John Byrne. The Phoenix entity previously manifested in Jean Grey in the PHOENIX SAGA in X-MEN  #101-108 (1976-77). The DARK PHOENIX SAGA depicts her corruption and demise. One of the most famous X-Men storylines, it is never really clear (then) if the Phoenix Force is a separate entity altogether or a part of Jean herself. The crimes of the Phoenix challenged the editorial and creative staff with rendering the only apparently acceptable ending--the death of Jean Grey. Jean's death would be undone in 1985 when Jean Grey joined the relaunch of the original X-Men in X-FACTOR , and the DARK PHOENIX storyline would be explored thoroughly in television, novels, and film, including a feature film, DARK PHOENIX in 2019.