<P> The first episode featured the return of many characters . Actress Samantha Smith reprised her role as Mary Winchester in a flashback, with Chad Lindberg making an appearance as the hunter Ash . Actor Gabriel Tigerman of the second - season episode "Simon Said" guest starred as the mind - controlling Andy Gallagher, and Katharine Isabelle of "Hunted" returned as the missing Ava Wilson . Other of Azazel's psychic children introduced in the episode were the heart - stopping Lily, portrayed by Jessica Harmon, and the super-strong Jake Talley, who is played in both episodes by Aldis Hodge . Actor Jim Beaver also guest starred in both parts as recurring character Bobby Singer, as did Fredric Lehne as the yellow - eyed demon Azazel . Lehne first portrayed the character in the second - season premiere "In My Time of Dying," and was originally meant to only play the part temporarily because the demon changes human hosts periodically . However, the show runners liked him so much they kept him in the role . Executive producer and director Kim Manners was happy with this decision, believing that Lehne brought to the character "a real Jack Nicholson flavor ." The second episode brought back actress Samantha Ferris as hunter Ellen Harvelle, as well as Jeffrey Dean Morgan as John Winchester, whose previous appearance was in the season premiere . Morgan's busy schedule required his scenes for the episode to be filmed weeks in advance . </P> <P> Multiple storylines spanning the first two seasons were brought to a close in the two - part season finale, including the search for the demon Azazel and the existence of Azazel's psychic children . As many of the show's questions are answered in one long conversation by Azazel, series creator Eric Kripke and writer Sera Gamble had to rewrite the demon's speech multiple times because they felt that "the payoff (was) never as good as the anticipation ." Though it would have been easier for them to keep postponing the revelations, the writers believed they would get "crushed under the anticipation" because they would not be able to satisfy fans if they kept building up more expectations . As for the psychic children, the writers originally intended to continue their storyline into the third season, but ultimately killed them off after deciding that the characters were not as interesting as demons and monsters . In the first version of the script, the character of Lily was two roles: a girl named Alex who could kill with a single touch, and a telepath named Lily . Believing they had too many characters, the writers combined Alex and Lily into one . Gamble had envisioned the episode as a "psychic Breakfast Club", so the new Lily's motivation was that she was Ally Sheedy . The Acheri demon responsible for two of the psychic children's deaths was based on the Acheri from Hindu mythology; writer Sera Gamble felt that it being a "diseased spirit" that comes down from the mountains and "kills everybody in the settlements" fit in with the abandoned mountain - side town that the episode takes place in . Harvelle's Roadhouse--a saloon frequented by demon hunters--was dropped from the show in these episodes as well, as Kripke disliked the concept of having a fixed home for a road - based series . With the Roadhouse's destruction came the death of recurring character Ash, whom the writers had been phasing out during the season because they felt his "comical" and "wacky" personality was too unrealistic for the show . </P> <P> With John Winchester making a demonic pact in the second season premiere, it was decided early on that the season would also end with another demonic pact . This required the writers to kill Sam--they felt it was the only thing that could motivate Dean to sell his soul--with the pact becoming one of the driving forces behind the third season . At the same time, it opened up another new storyline by questioning if what returned was "one hundred percent pure Sam ." Additionally, the "war of demons against humanity"--hinted at throughout the first two seasons--finally started with the release of demons through the Devil's Gate at the end of the second episode . This plotline continues throughout the rest of the series, with the Winchesters attempting to hunt down the demons in the third season . </P> <P> While the final version of "Part Two" is quite enclosed, the initial script was considered epic, with production designer Jerry Wanek jokingly referring to it as a "six - hour mini-series ." In the original version, the giant devil's trap keeping demons away from the gateway to Hell was much more complex, with each point in the pentagram being a church housing a holy relic--such as a sliver from the True Cross . With the artifacts powering the devil's trap, Jake's role would have been to go to each church and destroy them, the hunters following after him to try to stop him . Jake would then eventually destroy the final relic during a fight with Sam, and Dean would race to the gateway to prevent Azazel from opening it while Jake and Sam are "beating the crap out of each other ." However, when director and executive producer Kim Manners received the script, he realized it was huge, and had the storyboard artist make five - and - a-half hours of storyboards for the episode to prove that it could not be filmed without going hundreds of thousands of dollars over-budget . Production suggested that a large amount of money could be saved by not depicting the churches, which were major set pieces for the intended story . Kripke realized that instead of using churches, he could have the points of the pentagram be connected by railroad tracks . With tracks being made of iron, it fit perfectly with the series mythology because iron is a demon deterrent . Kripke found this aspect to be more Western, matching the tone of show . Rather than destroying the devil's trap as in the original script, Jake is instead sent by Azazel to open the gateway himself, and the major fight scene between Jake and Sam was then changed into a standoff between Jake and the hunters . Though the storyline had to be toned down, Kripke felt that this improved the overall episode by making it simpler . </P>

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