Since Season 6 started, fans have been worried and speculating that this may be the final season of "Once Upon a Time." The ABC drama has slowly been declining in ratings, leaving its future uncertain. ABC has yet to announce if the fan favorite will be renewed or canceled following the season 6 finale. However, this hasn't stopped fans from putting together theories, from the two part finale title "The Final Battle," which die-hard fans know is what Rumple predicted way back in the pilot. Fans were concerned when Henry announced in last Sunday's episode that his storybook is in fact in the last chapter.

What casting changes will occur if the show is renewed?

If the show is renewed, fans should expect some major cast changes. Its already been announced that the cast's contracts were up with season 6, and only four members were said to be in negotiations: Jennifer Morrison (Emma), Robert Carlyle (Rumple), Lana Parrilla (Regina), and Colin O'Donoghue (Hook). The rest of the cast could potentially serve as guest stars, but that is unclear. Though many are wondering where Rumple's storyline would go without Belle (Emilie de Ravin), and what this could mean for the fate of their son Gideon.

The question of casting changes was vaguely answered by showrunners Adam Horowitz and Edward Kitsis who promised that the finale will accommodate any changes made, and nothing will feel incomplete.

The end will answer who will stay and who will go, but they declined to share who those would be. Though, this would include original cast members, Gennifer Goodwin (Snow White) and Josh Dallas (David/Charming). ABC has also not confirmed who of the cast would be renewing their contracts. However, Kitsis shared that this will be the final chapter for some of the characters, and their stories would be complete.

He furthered teased that the fans will have to wait and see whether the endings for these characters would be good or bad. The season 6 finale will see the end of the first book, but the showrunners were excited for what could come as the next book if the show is renewed.

What to expect for tonight's episode

Adam Horowitz and Edward Kitsis tease possible deaths to come in the finale when Emma faces off in "the Final Battle," which fans learned referred to the fight between light and dark.

Fans were led to believe that this fight would be with Gideon, but last Sunday's episode revealed that he's been controlled by the Black Fairy who is in possession of his heart. Tonight's episode was teased as heartbreaking by Gennifer Goodwin, and will focus on the sacrifices they made for their family as well as an opportunity the Charmings may have missed to have reunited with Emma sooner than they did. Fans can also expect that the sleeping curse placed on Snow and David (Josh Dallas) to be a focal point.

"Once Upon a Time" ventured back to Neverland when Hook failed to find a way back to Storybrooke. Tonight's episode will follow Hook as he runs from the Lost Boys, who aren't so happy to see him.

Edward Kitsis teased that Hook worked for Peter Pan for several decades and so there will be those that have issues with him. They revealed that Neverland is no longer a place of immortality and magic, which Pan was darkening, but now a feral and wild place. Colin O'Donoghue excitedly teased that they will be showing more of Hook's past which he's always happy to do, as well as introducing fans to Tiger Lily, who revealed in the sneak peek that she may not be keen on helping Hook.

The season 6 finale of "Once Upon a Time" will air May 14 on ABC.