Once Upon A Time season 5
Emma Swan is seen mourning in Once Upon A Time season 5 episode 21ABC

Once Upon A Time season 5 returns with its penultimate episode on 8 May, where Hades will make his ultimate move and use the powerful Olympian Crystal to take over Storybrooke. Episode 21 is titled, Last Rites, which will air on Sunday at 8pm EST on ABC Network.

The official synopsis of the episode reads as follows:

Click here to watch the episode via live stream on ABC, or click here to watch it online on ABC's official website in the US.

Warning: Potential spoilers ahead

In the latest promo there is a scene where the Heroes are seen attending a funeral, which suggests that fans can expect the death of one of their favorite characters. The video shows Emma telling Gold, "Hades is in Storybrooke, we have to stop him." Meanwhile, Robin and Regina tell Zelena that they will do everything to protect their town.

This is followed by the voice-over saying, "The king of Underworld enters our world, igniting a devastating conflict that someone will not survive, breaking the very heart of Storybrooke forever." Hades then takes the Crystal and says, "This is not going to kill you, it is going to end you."

The video ends with a funeral, where Emma is crying and Regina looks heartbroken. Co-creator Eddy Kitsis spoke to The Hollywood Reporter about the episode and teased that "everyone should be frightened". Kitsis revealed that the pre-finale episode will be "very emotional" and "may break a few hearts".

Also, co-creator Adam Horowitz promised "we'll know where we're standing with living and dying characters" by the end of the episode, and that the death will be "[an] impactful, important piece of the storytelling going forward".

So, who do you think could die? Let us know your opinion in our comments section below.