One of Takeshi Kovacs' most interesting traits is how he can be merciless and violent, but, at the same time, compassionate and gentle. In the Netflix series' adaptation, these shades of his personality manifest multiple times throughout the story with many different people, and among them stand out Quellcrist Falconer and Kristin Ortega.
Quellcrist used to be the leader of a historical rebellion Tak had passionately become a part of, a revolution that ended with her temporary death and left him as the only survivor. Then, two hundred fifty years later, he met officer Kristin Ortega while living in her ex-boyfriend's (Elias Ryker) sleeve. He eventually returned the sleeve and left town to search for Quell (Altered Carbon season 2), but Kristin deeply got under his skin too. Here are the reasons why both couples are a good match.
Initially, Kristin was just keeping an eye on her ex-boyfriend's sleeve by following Tak around. However, when she and Kovacs started collaborating and learning more about the on-going cases and each other, they instantly connected and developed feelings for each other. She quickly became an important part of his life and, in an alternate ending, they could've had a fresh start together, away from his past, problems, and losses.
The "first love" stories in movies and tv shows are a classic, usually described as the strongest feelings humans can experience. Quellcrist and Takeshi have known each other for a long time and their relationship bloomed along with the rebellion. There's no real forgetting your first love, not even for Tak, who was completely lost without Quell in the first few episodes of the first season. Considering that they have been separated for two hundred and fifty years by external causes, they deserve to find their way back to each other and finally live their love.
Tak and Kristin working together is one of the best elements of season 1. The team managed to solve Bancroft's case, defeat Reileen, kill the Ghostwalker, and to finally get the two most powerful Meths behind bars. There was a lot of pain and obstacles along the way, but their energy was unmatchable throughout the whole season.
In terms of efficiency, the two of them managed to defeat more enemies and bring more justice than he and Quell or than Ryker and Kristin ever did! Together they're stronger, just like the season 1 finale proves.
Quellcrist's most pivotal trait was her intelligence and her untamable attitude. Her main goal was to bring equality and to reprogram the cortical stacks, which she considered to be the ruin of humanity; immortality corrupts humans and everyone knew that the division between rich and poor was almost unbearable. Takeshi had been a victim of that system too, therefore, he shared Quell's vision of the world and the intention of fixing it.
When Kristin and Takeshi met, their heart was in the same place. Both of them were assigned to Bancroft's mysterious case and, afterward, both lost their families and lovers. Thus, there was nothing left for them besides loneliness and anger until they entered each other's lives, which is possibly why they connected so deeply. They managed to heal and understand each other like no one else, at that time, could have.
Back in the rebellion era, Tak had just found his long-lost sister (Reileen) but had no place to go, since both The Protectorate and The Yakuza were hunting them down. After Quell convinces them to join her cause, Tak starts to bond with the members of the uprising, despite some initial hesitations.
He admitted to having found the support, tranquility, sociality, and overall humanity that he and his biological family lacked, especially after losing Reileen.
In the 7th episode of the first season, she went through a close-to-death experience; when she woke up in the hospital and looked at the sleeve, she pronounced Ryker's name, calling for him - visibly breaking Tak's heart (they had even slept together). In the season finale, however, as she woke up from the virtual reality she pronounced Kovacs' name, proving that her relationship with him wasn't all about Elias anymore. They could've both moved on; at least, Takeshi seemed to be the right person to take that step with for her.
Kovacs' first love story might've been Quellcrist, but it wasn't his last one. On the contrary, Quell hasn't found another lover, unlike Kovacs and Kristin did, therefore she's not emotionally and romantically attached to no one else besides him. It is true that Ortega could've moved on, but Quell didn't need to: she kept on living in Tak's head and he kept living in her heart the whole time, for almost three centuries.
In the first season finale, Reileen's threats continuously pressured Tak to choose, and eventually kill, between his sister and Kristin. Tak points then gun at his cortical stack while looking at Ortega and after she begged him not to shoot himself, he pulled the trigger. The gun was unloaded, but Tak's reaction and his steady gaze on Ortega proved that he was willing to die for her. Those are the kind of feelings you don't easily get over, even when Quell is still part of the picture.
However, Takeshi and Quellcrist continuously prove that the only thing that can separate them is real death. Tak stopped looking for her because he thought she was dead, meanwhile, she had lost her memories and did not remember him. As soon as Reileen revealed that Quell was backed-up in another stack, he lighted up with hope again and even went to another planet, Harlan's World, searching for her.
