The fifth season of the American ABC fantasy-drama series Once Upon a Time was ordered on May 7, 2015. It began airing on September 27, 2015, and ended on May 15, 2016. On June 9, 2015, the promotion of Rebecca Mader and Sean Maguire to series regulars was announced for the fifth season, portraying their characters Zelena / Wicked Witch of the West and Robin Hood, respectively, while a few days later, Michael Socha was confirmed to not be returning as a series regular as Will Scarlet / Knave of Hearts. The season also saw the series reach its 100th episode, which aired on March 6, 2016 as the mid-season premiere.
Existing fictional characters introduced to the series during the season include the main antagonists for the two volumes, King Arthur, Nimue and Hades, alongside Guinevere, Merlin, Merida, Percival, Hercules, Megara, Zeus, Poole, Jekyll and Hyde. The season also saw the return of numerous deceased characters from previous seasons, including the Blind Witch, Cora Mills / the Queen of Hearts, Peter Pan, Cruella de Vil, Baelfire / Neal Cassidy, Milah, Prince Henry, Liam Jones, Prince James, Gaston, Claude, and Stealthy.
Premise
With Emma having become the new Dark One, her family travels to Camelot to find the sorcerer Merlin, in a bid to remove the darkness from her vessel. The heroes then met King Arthur and Queen Guinevere of Camelot, with both on the hunt of the Dark One's dagger to make Excalibur whole. The trip to Camelot is cut short when another Dark Curse is cast, returning everyone to Storybrooke, where it is revealed that Hook had also become a Dark One and is responsible for the new curse. The battle to destroy the darkness leads to the death of Hook, prompting Emma and the heroes to take a trip to the Underworld where Hades, as well as most of the deceased villains, have plans of their own to get back to the land of the living. Hook is eventually resurrected, but a bid from Mr. Gold to capture all of Storybrooke's magic results in the arrival of Mr. Hyde and refugees from the Land of Untold Stories to Storybrooke, as well as the separation of Regina Mills and her evil self, who wages war on Regina.
