Hades (Hercules)...
Hades, voiced by James Woods, is the villain in the 1997 movie Hercules, based on the Greek god Hades. Unlike the mythological Hades, who is for the most part a relatively passive deity doing a sometimes nasty job, this version is a fast-talking, evil deity, reminiscent of Satan. The character's mannerisms were due to James Woods ending up using a "car-dealer"-style voice while the movie was being made. His hair is blue fire, and whenever he gets upset, it flares and becomes red (for common carbon-burning fire, blue indicates a hotter flame than red). His hair-flame has also been shown to flare when he grows particularly excited (when the Fates tell him he will overthrow Zeus), although in this case it remains blue.
Hades sent his two demons, Pain and Panic, to kidnap baby Hercules and give him a potion that would render him mortal. Hercules needed to drink every last drop for it to work, but when a human couple comes along, the demons drop the bottle, breaking it and losing the last drop. Thus, Hercules became a demigod and spent his life on Earth.
Later, a young woman named Megara, or Meg, sold her soul to Hades so that he would rescue her lover. He did, but soon Meg's lover fled for another girl (possibly under Hades' influence, though it's never specified). Meg was stuck doing tasks for Hades.
Hades sent numerous threats to kill Hercules, such as the Hydra, but none worked. When he found out that Hercules had fallen in love with Meg, he took this to his advantage and made a deal with Hercules. He asked Hercules to give up his powers for twenty four hours (when he was set to overtake Mount Olympus) in exchange for Meg's freedom. Hercules agreed, as long as Meg wouldn't be hurt.
Hades attacked Mount Olympus with the Titans and succeeded in overthrowing Zeus without Hercules to stop him. The Cyclops was sent to Earth. Hercules, despite being powerless, managed to take down the monster, using his wits instead of his strength.
However, Meg was fatally crushed saving Hercules from a falling pillar. This negated Hades' deal that Meg would not be hurt. Hercules was thus given his powers back and returned to Mount Olympus where he easily took down the Titans and freed the gods.
Hades was furious, but he taunted Hercules that he at least had a parting gift: Meg's soul. Hercules traveled to the Underworld to rescue her. He swam into the River Styx to retrieve her soul. It almost killed him, when his full Godliness was restored by willing to risk his life to save Meg. Hercules emerged from the pit.
Hades begged the hero to try and ease things with him and the other gods, but Hercules decided to let Hades spread his evil no longer and punched him into the River Styx, where he was swarmed by the Spirits of the Dead. Because he's a god he's currently still alive but is trapped in the river.
Hercules: The Animated Series
Later, with the return of Hercules on the form of an animated series, Hades also re-appeared, and had many appearances trying to take over the Olympus. One episode even had a crossover where Jafar makes a deal with Hades, in order to make Hercules and Aladdin fight each other. Hades once was a black belt.
Mickey's House of Mouse
Hades appears a few times in the House of Mouse full-length spin-off Mickey's House of Villains; however, James Woods only provides the voice for one line ("Ha - love that", in response to Mickey's joke, "Why, I even saw Hades - he was really paintin' the town dead!"). Rob Paulsen provides the singing voice when Hades sings the lines "Where everyone's a friend of mine!" and "What a place for breakin' bread!" in the song "It's Our House Now!"
During the actual House of Mouse series, Hades serves as comic relief. In one episode he complains that his coffee was mistankly decaf, to which Gaston (Beauty and the Beast) replied "Nobody makes decaf like Gaston", a running gag that gets on Hades' nerves. In another episode, Mickey runs past him so fast, the flames on his head go out. However, he uses Lumiere to light it again. Yet another episode was dedicated strictly to him, in which the air conditioning breaks, driving away all of the guests except Hades, who comments that it feels "just like home." Mickey and friends then attempt to make Hades as comfortable as possible to prevent him from leaving (The House's contract states that should the place be completely empty, it will be closed down). He eventually leaves after the House is flooded, but thankfully it serves as a perfect environment for the Little Mermaid characters. In this same episode, Hades is greatly pleased to see Chernabog from Fantasia perform what he calls "the old act" (A basic reprise of Chernabog's performance in the actual Fantasia movie).
In another House of Mouse episode, Hades is attracted to the female villain Maleficent and does everything to attract her attention. When every idea backfires he scolds Mickey angrily by casting himself in flames. Maleficent notices him and thus asks him to sit next to her.