Hades

"Each clock tick means a soul has left my domain. Do I look like I like to lose anything?"

Hades is the devilish ruler of the Underworld, who appears to have something against the heroes who have arrived to rescue Captain Hook.

Before the Curse
When Captain Silver prepares to sail his crew into the center of a storm in order to retrieve the eye of it, hoping to win great reward, he is taken down last minute by the Jones brothers, Liam and Killian. However, with the storm appearing to worsen, Liam goes below deck where soon he is met by Hades, Lord of the Underworld. Hades wishes to make a deal with the sailor, agreeing to help secure his future as a captain. He wishes for Liam to help sink the ship, thus sending the whole crew to the Underworld, and in exchange he will give him the eye of the storm that Captain Silver was originally after, a jewel the King will pay generously for. Liam contemplates this, and soon enough he gives in, allowing the entire crew to be drowned at sea while he and his brother Killian are able to wash to shore. Liam holds onto the eye of the storm when met by naval guards, and as reward, he and Killian are both welcomed with opened arms.

Season 5
Having come to learn of the arrival of the heroes in the Underworld, Hades sends Cora out to convince Regina to leave, and to preferably take Henry and Robin with her. Things don't go as planned though, and instead of getting Regina back to Storybrooke, Regina gets her father to move on from the Underworld, for his closure with his daughter meant the resolution of his unfinished business. Having failed at the task she was instructed to see through, Cora returns to Hades' lair beneath the Underworld library, where Hades is found receiving a pedicure. Despite failing, Cora still insists Hades hold up his end of the bargain, that being something having to do with assuring Regina's wellbeing, something Hades points out to be surprising, considering how she treated her other daughter, Zelena. Cora is surprised to learn Hades' knowledge of the child she once abandoned, but as punishment for failing him, she is restored to the role she once served as a miller's daughter, that being to rags and forced to spend eternity delivering flour.

When Hook helps Megara escape from Hades' prison, the ruler of the Underworld has his guards bring the wounded pirate (who had just battled Cerberus) to his lair. He calls the three-headed beast off from attacking the heroes, choosing to instead confront them himself. Upon meeting with the heroes, who have enlisted the help of Hercules, Hades takes the opportunity to shame the demigod for how he died, while also refusing to explain why the Underworld is based after Storybrooke. In order to add further salt to the wounds already created, Hades leaves Emma with her lover's bloodied hook, considering it to be a message; he tells Emma she shouldn't fear what has already been done to Hook, but what will be done to him. Mary Margaret, with Hercules and Megara's help, ends up killing Cerberus, thus fulfilling Hercules and Megara's unfinished business, allowing them to pass on to Mount Olympus. This infuriates Hades, who now believes Hook's rescuers have caused too much damage since their arrival. Giving Hook a rasp for carving into stone, he then materializes three unmarked headstones, declaring that for every soul the heroes save, Hook will be in charge of choosing which of his friends have to stay in the Underworld forever.

Since Hook refuses to choose three of his friends to sacrifice for helping souls with unfinished business move on, Hades decides to punish him by hanging him over the River of Lost Souls, hoping to wipe away any hope the Pirate has left before he hits the water. He plans to do away with the others who have infiltrated his realm, and to do this he finds Rumplestiltskin, who is in the process of helping Emma and Milah rescue their shared love. Rumple is taken to Hades lair where a deal is formed: Rumple will do away with the boat found to escort everyone home in exchange for his own passage back, thus allowing him to continue his reign as the Dark One without the heroes interference. Knowing he has no other choice, seeing as how Hades knows of their every move, he gives in and destroys the boat while throwing Milah into the River of Lost Souls before Emma returns with a rescued Hook. Rumple later meets with Hades for his ride home, but Hades now has other ideas; he's come to learn something about the Dark One, that being his wife Belle is pregnant with Rumple's second child. Hades has also found out that Rumple once made a deal with a healer that involved turning over his second born... a deal that has now been turned over to Hades. Using the contract as a means of blackmail, Hades forces Rumple to work for him, threatening to take away his and Belle's child if he refuses.

Gallery
Gallery of photographic stills released to promote the character.