Mass Effect is a series that I really enjoy playing though to be honest I cannot bear playing/finishing the third game because there's basically no way to save Shepard. I mean there's one way but you have to have a perfect game and even then Shepard is stranded with no one coming to save you so basically Shepard is dead anyways. I just couldn't bear myself to get to that point in the game. Especially after you have to watch Shepard deal with the mental hardship of seeing all the death over the series. It's just a bit too much, but I will for sure play Andromeda when it is released. But it's in the future, so it's definitely not going to be you playing as Shepard anymore.
One thing that really interested me during the course of the games was how Artificial Intelligence evolves and is treated during the games. You mainly see this through the reapers, the Geth, and EDI. Each are treated differently throughout the game by Shepard and by the entire world of Mass Effect.
These are creatures that were created when an organic life form becomes so advanced that they are deemed that they need to be terminated so the life cycle of the universe can start over again. Mainly these are treated as the bad guys meant to be killed/stopped. You can choose to either research the creature after the final battle of Mass Effect 2, or just destroy it. And then in Mass Effect 3, your main choice is to you destroy the reapers, control the reapers, or synthesis with them so everyone becomes part AI. But you have to have high military strength or it just all ends in death/destruction.
These were originally a machine created to help the quarians, but over time got more abilities and a hive mind to the point where they became A.I. This caused the quarians to be exiled from their home planet and then these creatures began to treat the Reapers as Gods. So for the most part they are the enemy as well throughout the games. But in Mass Effect 2, you can add one to your companions and decide if Geth with a malfunction in coding to be destroyed or changed so they no longer attack.
This is made for the Normady, Shepard's ship, by Cerburus in Mass Effect 2. EDI doesn't have full control of it's action until the end of Mass Effect 2 when the Normady is attacked by the the Reapers. And in Mass Effect 3, EDI gains a body of her own. This is the one character that's an A.I. besides the geth named Legion that isn't treated as an enemy overall. But you get to choose if it's fine for EDI to have a relationship with Joker or not. Which I find interesting as throughout the series, the general attitude towards A.I. is that they are not to be trusted and should be destroyed. Whereas, EDI is one that you honestly treat as a friend of yours.