What Is the Cortana System in Halo & How It Differs from the Games?


While a good part of the entire Halo universe focuses on Master Chief Petty Officer John-117, probably the second-most important character in the franchise is Cortana. The Halo TV series finally revealed its version of Cortana in episode 3 when it was integrated with Master Chief through the efforts of Dr. Halsey. So, what is the Cortana System in the Halo show, and how does it differ from the games?

The Cortana System, or simply Cortana, is an artificial intelligence system developed by Dr. Catherine Halsey using a clone of her brain. Cortana’s purpose is to serve as a companion AI to Master Chief in Halo and is supposed to take over his entire body but serves as a partner instead.

Cortana is one of the most important characters in the entire Halo franchise because of how big a role she has as Master Chief’s companion. That said, it is interesting to see how the TV series proceeds with her character and how she is going to help shape the events in the future. That said, let’s look at what we know about the Halo TV series version of Cortana.

What Is Cortana In Halo?


Everyone who knows a thing about the Halo video game franchise would know that the most important character is Master Chief Petty Officer John-117, or simply Master Chief. After all, he is the face of the franchise and has been the main character of all of the main Halo games since the very first release in 2001. Of course, one character is almost just as prominent as Master Chief.

The second-most important character in the entire Halo franchise is Cortana, who isn’t exactly a person. Since her introduction in Halo: Combat Evolved, she has been the AI companion of Master Chief and has always been with him until her “death” in Halo 4. Still, she returned in Halo 5: Guardians and is one of the most important characters that shaped the events of Halo Infinity.


All 16 Halo Games in Order

In that regard, there is no doubt that Cortana is one of the most important characters in the entire franchise. That means that she was eventually going to make her live-action appearance in the Halo TV series on Paramount+.

It took three episodes for the series to finally reveal Cortana to the audience as she made her on-screen debut in episode 3 of the series. Considering that not all of the people who are watching the Halo TV series are familiar with all of the characters, it is important for us to talk about who Cortana is in the Halo show.

In the games, Cortana, as mentioned, is an AI companion that aids Master Chief in his on-field missions and is seemingly “attached” to him in the sense that she is integrated with him. She often analyzes data and does the numbers crunching in the entire Halo video game franchise while also offering valuable information to Master Chief so that the Spartan could focus more on his mission and could undertake his missions in a more efficient manner.

Cortana is actually a creation of Dr. Halsey, who you might be familiar with as the one who started the entire Spartan-II Program. She created Cortana by flash-cloning herself and by using the brains of her clones to create an AI system that was designed to have her magnificent brainpower and a portion of her thought process.

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Out of the 20 clones, only two were able to survive. The other brain was used on an AI called Kalmiya, who is also just as smart as Cortana but was not as important in the Halo games. She “died” in 2552, and that means that Cortana is the only remaining AI program designed after Halsey’s brain.

In the Halo TV series, Cortana was created in a similar manner. Dr. Halsey created a flash clone of herself and used the clone’s brain to create Cortana, who she said was supposed to be able to completely take over a Spartan and control their body. In this case, the Spartan we are talking about is Master Chief.

Cortana’s purpose in the Halo series is to serve as some sort of a system that could control the Spartans so that they would become more compliant with their directives. This came about as a result of Master Chief going rogue in episodes 1 and 2 of Halo before he returned to the UNSC at the end of episode 2. 

On top of that, Cortana also serves as a system that could help the Spartans when it comes to analyzing data and crunching the numbers. You can think of her as an autonomous smartphone companion in the sense that she is able to do all of the analytical stuff while the Spartans focus more on the action happening on the field.

Of course, for those who don’t know, the Cortana on the show is portrayed by the voice actress (Jen Taylor) of the Cortana in the games. However, her appearance in the series is more in line with her real-life appearance. Meanwhile, Cortana’s design in the games has changed from one game to another.

Cortana’s history and purpose in the games and the series are quite similar to one another. Still, there are some differences between them. And that’s what we are going to talk more about as we proceed with this discussion.

How Does The Cortana In The TV Show Differ From The Games?

While we did mention that Cortana’s history and functions in the games and the live-action series are similar to one another, we do know that the Halo show isn’t shy about introducing changes to the characters and events. In that regard, there are also some differences between the Cortana version in the games and the one in the series.

The first difference between the Cortanas is how they were introduced to Master Chief. In the games, Cortana specifically chose John-117 because of his track record and his abilities as a Spartan when compared to the other super-soldiers serving the UNSC. However, in the series, Halsey was the one who chose John-117 to be Cortana’s companion because of Master Chief’s relationship with the artifact that they found on Madrigal.

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Meanwhile, in the Halo series, Cortana’s main purpose was to actually take over the Spartan’s body and basically have full control over them. Nevertheless, Halsey decided to limit Cortana’s access to Master Chief’s body because she felt that his connection to the artifact and his memories were important to finding more about the secret of the artifact itself. It was never established in the games that Cortana could take over a Spartan’s entire body.

Then there’s the fact that Cortana’s relationship with Master Chief in the games is actually quite interesting because they care for one another and may even have feelings to the point that Cortana often jokes that she is in a relationship with John-117. Meanwhile, Master Chief cared so much about Cortana that he went rogue in Halo 5: Guardians when he had a reason to believe that Cortana was still out there somewhere.


Is Master Chief In Love With Cortana (& Why)?

On the other hand, Cortana’s relationship with Master Chief on the show is quite rocky because John-117 didn’t even want her around. There were moments where he felt annoyed by her presence and was actually feeling like Cortana was intruding on his privacy. However, this may only be the beginning as we may see them having a better relationship in the future.

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