Cosima Niehaus, Orphan Black
Cosima Niehaus (Tatiana Maslany)
Cosima is a ph D. student and one of the clones of Sarah Manning. Cosima, Alison Hendrix and Sarah grouped together to form “Clone Club”, in order to find out where they come from. Cosima is suffering from an unknown respiratory illness.
In 1×05, after finding out that one of their other clones gets monitored in a science experiment, Cosima met Delphine and the two quickly grew closer over their love for science. Despite warnings from Sarah, Cosima continued to see Delphine, convinced she couldn’t get hurt. Delphine seduced her in 1×08 in order to ransack her apartment and betrayed her to her employer. When Cosima found out, she was angry and the two fought but eventually Delphine chose Cosima’s side in the Season 1 finale.
Cosima and Delphine teamed up and got back together to fight Cosima’s disease for most of the Season. When Delphine found out the Dyad institute used stemcells from Sarah’s daughter for Cosima’s treatments she withheld the information. Cosima found out, was angry, and they broke up again although they got back together an episode later, and exchanged “I love you”s (2×08).
In the premiere episode, Delphine broke up with Cosima, and distanced herself from her, presumably in order to protect her and the other clones, though both Delphine and Cosima were clearly heartbroken. Delphine did not appear again until 3×06. Cosima went on a Tinder date with a girl named Shay in 3×05, brought her back to her place, and they started a brief relationship. Meanwhile Delphine became obsessive, started spying on Cosima and Shay and (with Cosima’s knowledge), interrogated and threatened Shay in 3×09. Cosima and Delphine kissed again in the Season 3 finale, before Delphine was shot and apparently killed.
In Season 4 Cosima, still dying and looking for a treatment, lost herself to PTSD and survivor’s guilt after Delphine’s death. Despite the series producers’ insistence to fans and media that Delphine was really dead and off the show for good, she returned at the end of Season 4 when it was revealed that she was alive and had been taken captive rather than murdered. Felix managed to talk Cosima down from a suicidal plan with the news (4×07). Cosima and Delphine are reunited in the finale.
In an interview with TV Line, executive producer Graeme Manson revealed Delphine would return in Season 5:
“In some capacity, for sure. It was always our desire to bring Delphine back, and we had to play tight-lipped and deflect and lie and keep our secret last year. It wasn’t easy or pleasant. But these are the vagaries of actors with busy schedules. I don’t know what it looks like [next season], but again, we’re going to do our best to let the story of Cosima and Delphine play out through the show.”
Female love interests:
- Delphine Cormier (Évelyne Brochu, bisexual, recurring)
- Shay Davydov (Ksenia Solo, lesbian, recurring)
Relationship story arc with a woman: Yes
No male love interests
Relationship story arc with a man: No
Male love interest after being identified as a lesbian? No
Filter Relationship Arc:
Storyline during sweeps? No
 A relationship story arc is defined as explicit, developed on screen, and lasting more than 3 episodes. It is listed as questionable or subtext if romance is only implied, mentioned instead of shown on screen, part of a dream sequence, or otherwise not explicit for the viewer.
 Sweeps episodes air in February, May, July and November, the periods when advertising rates are set. A character is marked as "sweeps" when there is a very limited number of episodes that address their sexuality, all air during sweeps period, and the storyline is otherwise ignore/dropped.