Before the world fell in love with dragons, Mandalorians, and trying to figure out which reality Wanda and Vision are living in, there were two machines on a crash course for either greatness or destruction. Person of Interest placed humans as the builders of two of the best Artificial Intelligence Units ever made and watched as they either tried to help to take over the world.
A great dialogue show must have top-of-the-line characters. Person of Interest was able to hit major marks with characters fans either cheered for or against with no crossover appeal. John Reese and Harold Finch set the stage and brought in reinforcements that fans related to as they dealt with villains fans wanted to see fail.
John Greer
Harold Finch vs John Greer is the classic case of good vs evil. Every hero needs a villain and for a while that was Root. But then Greer took over with Samaritan and Finch and The Machine had their first real formidable for. Greer was former MI6 who vanished then reemerged with his eyes on Finch and The Machine.
Greer wanted to rule the world. Or better yet, have the control at the tip of his fingers. But Harold and his team were standing in the way. Soon, Greer would learn the hard way that no matter how intelligent you think you are, what you thought you control, will eventually control and destroy you.
Samaritan
The Machine's purpose was to save lives. It knew who would be in danger and it was up to Finch and John to prevent the chaos from happening. But Samaritan, that AI was a different ballgame. Falling under the same umbrella, Samaritan was designed to be a better version of The Machine.
Samaritan started off good but then choose to play a game of its own. The Machine was loyal to Finch while Samaritan was loyal to itself. Samaritan would take out anyone it felt was disloyal to its cause, and in turn, the ultimate battle between The Machine and Samaritan would take place.
Lionel Fusco
Lionel went from a dirty cop to a hero. Before John and Finch came into his life, Lionel was doing the dirty deeds of the criminal underworld. Part of a group of rogue cops, Lionel was on the wrong side of the law on more than one occasion. But he managed to turn it all around and won over the hearts of some of the fans in the process.
While his actions made him a target for those same dirty cops he used to run with, Lionel knew he had protection from his new team. The storylines surrounding Person of Interest were serious but Lionel did provide comedy relief.
Joss Carter
Joss was supposed to be Sameen or Root before either ever stepped into the storyline. Joss was the cop looking to take down John when it was believed he was just on a vigilante crusade. But as she would learn, the story was much deeper than that. John would eventually tell Joss the truth and while she wasn't an official member of the team, there was an olive branch extending.
Her death changed the direction of the show. For a moment, it appeared as if Joss and John would become an item but neither acted on it. A single mother, Joss was good police officer all the way up to her death.
Sameen Shaw
John needed help. There was no way he could keep saving the lives of those in the city by himself. Sameen was just as tactical and fearless as John. Her presence can be seen as foreshadowing to what MCU fans have come to love about Black Widow.
Her capture caused concern and added an element of surprise to the storyline but by that time, the show was winding down and it was too late to save it. Sameen didn't have much of a life outside of the team and that's where the writers made their mistake with John. Root was in love with her and would ultimately give her life to save Sameen's.
The Machine
Despite most characters in shows being in the physical, Person of Interest took their cues from a computer. The Artificial Intelligence character was the real star. She saw things most didn't and knew exactly when to strike. It was up to the team to stop the threat.
There were moments where The Machine was just that. A machine that spits out valuable information but as the seasons grew, so did the machine. As robotic as it was, The Machine became more human thus resulting in a sense of humor and deadly intentions at times.
Carl Elias
Elias was the mastermind no one saw coming. His interactions with John in the beginning stages was classic TV. The dialogue between the two was great and the respect each held for the other made the paring memorable. Elias controlled a large portion of New York but when his position was threatened, fans witnessed just how dangerous Elias could be.
Over time, viewers grew to respect Elias the same fans have done with Raymond Reddington in The Blacklist. He sacrificed plenty to keep more than his position safe. For Elias, it was about the integrity of the business he wanted to keep on solid footing.
Harold Finch
Harold Finch was more than a nerdy computer geek with glasses and a hidden past. He was the savior. Yes, it was John out in the field doing the grunt work but it was Finch who found, cleaned up, and gave John a purpose for living. Although he knew that John's time would wind down, Finch managed to make him a believer in all that was good.
His creation saved lives on a daily. And when The Machine went haywire, it was John who brought it back. Easily the unofficial leader of the team, Finch was more like John Snow from Games of Thrones. He held the power, but he himself was not willing to accept being called the leader.
John Reese
John was the down on his luck guy who just needed a sense of direction after everything he loved and believed in was lost. For MCU fans, Reese is similar to The Punisher in that sense. Armed with a special set of skills used against those trying to manipulate the system and cause harm to innocent people.
With Finch leading the way, John set out on a mission to help those in need. His storyline, much like Frank Castle's were filled with bouts of violence, revenge, and regrets.
Root
Every great show needs that one character who can play hero and villain. For Person of Interest, that was Root. She wanted to beat The Machine and Root vs Finch vs The Machine was a classic battle. Root was hard to stop. She was well-trained in different facets of attack that even the team of John, Finch, and Sameen couldn't stop her.
In the later stages of the show, the writers thought it would be a great idea to team her up with John and Finch. In mant ways, watching her was like watching Elektra. She played both sides of the fence and brought a missing element to the show.