Season one In "Tigh Me Up, Tigh Me Down", Commander William Adama returns from a mysterious off-ship errand, accompanied by Colonel Saul Tigh's wife, Ellen, who Tigh assumed had been killed in the devastating Cylon attacks on the Twelve Colonies. Ellen explains that she was at the airport on
Picon when the Cylons attacked, and after being knocked unconscious, was rescued by a stranger. She has no memory of the intervening weeks, during which time she was nursed back to health on another ship, the
Rising Star. Suspicious of Ellen's sudden reappearance, Adama tasks Dr.
Gaius Baltar (
James Callis) to submit her blood sample to his newly-invented Cylon detection test. Though it is clear to President
Laura Roslin (
Mary McDonnell) that Tigh loves Ellen deeply, Adama laments that Ellen has always been a bad influence on Tigh, bringing out his self-destructive qualities. Both drunk, Tigh is annoyed when Ellen flirts with Baltar in front of him, which she deflects by lying that Adama has made advances to her. The Tighs confront Adama in Baltar's lab, where he is explaining to Roslin and his son,
Lee Adama (
Jamie Bamber), how he had been keeping Ellen at a distance for as long as he could, both because of his suspicion that she might be a Cylon, and because of her history as a negative force in Tigh's life. Baltar declares Ellen human, but a conversation with
Head Six (
Tricia Helfer) reveals that he intends to do so for everyone, and he may be lying about Ellen's results. In "
Colonial Day", Ellen shakes hands with terrorist-turned-politician
Tom Zarek (
Richard Hatch) in public, immediately after Tigh refuses to. She wants their picture in the media, and predicts that Roslin is on the way out as President and Zarek is the future. Later, Ellen tells Zarek she has ambitions for herself and Tigh, and he asks her for help finding his "friend". This friend, a would-be assassin sent to kill Roslin but captured by Lee and
Kara Thrace (
Katee Sackhoff), is subsequently killed before he can implicate Zarek in the plot.
Season two In "
Scattered", Adama is in critical condition after being shot, and Tigh reluctantly takes command of
Galactica. Anticipating that Adama may die and sensing weakness in Tigh, Ellen goads him to seize control, but he shuts her down. In "
Fragged", Ellen assumes that Roslin's confused and slightly delirious state is a mental breakdown, when in fact she is suffering withdrawal from her cancer medication. Learning that Tigh is under pressure by representatives from the Twelve Colonies to give them access to Roslin, Ellen encourages him to do so, believing the sight of Roslin in her current condition will undermine her authority, and leave Tigh in unchallenged command of the ship and the fleet. The plan backfires when Roslin accesses her medication and denounces Tigh, who declares martial law. In "
Resistance", a number of ships refuse to resupply
Galactica in protest. Tigh is unsure what to do, and Ellen berates him, urging him to assert himself. Tigh's subsequent threats to the protesting factions result in a riot in which Colonial Marines kill four civilians. Tigh is bitter over Ellen's manipulations, but she is unapologetic, later encouraging him to fire on a ship carrying Lee and Roslin as it flees the
Galactica. Adama appears and resumes command, sending Ellen away. Tigh receives a death threat in "
Final Cut", and an assassination attempt against him is averted. He and Ellen are subsequently confronted at gunpoint by a Marine disgruntled over the civilian deaths Tigh's actions caused. In "
Sacrifice", Ellen is one of several hostages taken by would-be terrorist
Sesha Abinell (
Dana Delany), who demands that Adama hand over the imprisoned
Number Eight Cylon copy so she may exact revenge for her husband's death in the Cylon attacks. Lee uses Ellen's attraction to him to manipulate her as part of his plan to distract Sesha's team. The humans settle on a habitable planet they call New Caprica in "
Lay Down Your Burdens", but a year later, a Cylon fleet arrives and places the planet under occupation. Though they promise peace, Tigh is among those who vow to resist.
Season three Four months later in "
Occupation", Tigh is in a Cylon detention center for his Resistance activities, and has lost an eye. Ellen performs sexual favors for one of the Cylon
Cavil (
Dean Stockwell) models to effect his release. She continues doing so in "
Precipice" to guarantee Tigh's continued safety. Cavil next demands information on an upcoming Resistance meeting under threat of having Saul arrested or killed. Ellen pockets a map to the location where the Resistance plans to rendezvous with an emissary from the
Galactica, and the meeting is ambushed by Cylon Centurions. In "
Exodus", Resistance member
Sam Anders (
Michael Trucco) realizes that Ellen is the one who betrayed them. He tells Tigh that if he does not "take care of" Ellen himself, less sympathetic members will, as any betrayal of the Resistance is punishable by death. Ellen confesses to Tigh, explaining that she loves him and would do anything to save him from harm. While holding her and telling her he loves her, Tigh gives Ellen a poisoned drink. She dies seconds later, and he weeps over her body.
Season four Tortured by the recent revelation that he is one of the
Final Five Cylons, Tigh confers with an imprisoned Caprica Six, but continually hallucinates Ellen in Six's place in "
Escape Velocity" and "
Sine Qua Non". His arrival on a devastated Earth in "
Sometimes a Great Notion" triggers Tigh's memories of having been there 2000 years before, during the nuclear cataclysm which destroyed the planet. In that distant past, a dying Ellen says "Saul, it's okay. Everything's in place. We'll be reborn ... again. Together." Tigh realizes that she is the last of the Final Five Cylons. In "
No Exit", Ellen is resurrected aboard a Cylon Resurrection Ship after her death in "Exodus", but held captive there by Cavil. Her resurrection restores her memories of her true nature. It is revealed that the so-called Thirteenth Tribe, which had left the planet
Kobol at the same time as the 12 tribes of humans which would become the Twelve Colonies, had been an early iteration of humanoid Cylons. They settled on Earth, and their resurrection technology was lost as they became able to reproduce sexually. Eventually, Ellen and the other four of the Final Five rediscovered the technology in time to survive the destruction of Earth by their own version of
Cylon Centurions. Aboard their own resurrection ship, the five traveled to the Twelve Colonies to warn them of the danger of
artificial intelligence, but without
faster-than-light drives, the journey took 2000 years. They arrived to find the Colonies already at war with their own Cylon Centurions. To end the war, Ellen and her colleagues gave the Caprican Centurions resurrection technology and eight models of humanoid Cylons, imbued with human characteristics like love and mercy to prevent war. However Cavil, the Number One model, became convinced that humanity was evil and undeserving of survival. He murdered the Five, and placed new copies, their memories altered, among the humans to suffer along with them. After destroying the entire line of
Number Sevens, Cavil orchestrated the infiltration of copies of the remaining seven models into the human race as both self-aware and sleeper agents. In the present, Ellen urges Cavil to end his persecution of the humans, but he refuses. The Cylons' resurrection technology has been lost via the destruction of the Resurrection Hub by the humans in "
The Hub". Cavil demands that Ellen restore the technology for them, but she stalls by saying she needs the other four of the Five to do so. Before Cavil can have the information extracted from Ellen surgically,
Sharon "Boomer" Valerii (
Grace Park), a Number Eight model, helps her escape from the Resurrection Ship. Ellen and Boomer return to the
Galactica in "
Deadlock", where rebel Cylon models
Two (
Callum Keith Rennie), Six, Eight and the last remaining
Three (
Lucy Lawless) have formed an alliance with the humans. Ellen is shocked to learn that Tigh has gotten Caprica Six pregnant, as Ellen and Saul were never able to have children. The Final Five vote over whether they and the rebel Cylons should leave the human fleet to go in their own direction.
Tory Foster (
Rekha Sharma) and
Galen Tyrol (
Aaron Douglas) vote to leave, while Tigh, and Sam Anders by proxy, vote to stay. Ever frustrated by her perception of Tigh's devotion to Adama over her, Ellen breaks the deadlock and votes to depart. Six's subsequent miscarriage prompts Ellen to admit that her vote was intended to hurt Saul, and she does not want to leave. In "
Someone to Watch Over Me", Ellen realizes that Cavil orchestrated her escape so that Boomer could abduct the human-Cylon hybrid child
Hera (Iliana Gomez-Martinez), daughter of
Karl Agathon (
Tahmoh Penikett) and another Eight copy, Sharon "Athena" Agathon. In "
Islanded in a Stream of Stars", Ellen consoles Tigh, who is grieving his lost child, by reminding him that he is the father of millions of Cylons. They help orchestrate the rescue of Hera from the Cylon "homeworld", a sprawling basestar called The Colony, in the series finale "
Daybreak". The surviving humans find and settle on a second, pristine Earth, and the Tighs decide to spend the rest of their lives there together.
The Plan In
Battlestar Galactica: The Plan, a pair of Cavils monitor a set of resurrection tanks containing copies of the Final Five, two weeks before the cataclysmic Cylon attacks on the Twelve Colonies. They expect that the originals will be killed and resurrected, and with their memories restored will apologize for their appreciation of humans. Later, Ellen is in a bar on Picon talking to a mysterious stranger, one of the Cavils who wishes to experience the planet's destruction firsthand. He is annoyed at Ellen's suggestion that people cannot, and should not, change who they really are. She is severely injured by the blast that destroys the bar, but Cavil assures her cryptically that she will not die, saying "Your suffering isn't over yet, not when you've got so much left to learn." Cavil keeps Ellen alive as he feels she has not learned her "lesson" yet. They are evacuated from the planet in a Raptor, and Ellen ends up on the medical transport ship
Rising Star, where she slips in and out of consciousness for weeks as she recovers from her injuries. As the fleet of Colonial survivors, led by the Battlestar
Galactica, flees the pursuing Cylon forces, Cavil visits Ellen during the events of "33", and she asks him to find Saul. Cavil believes it is both cruel and necessary to keep her alive, as in all the years she has lived among the humans, she has "failed to observe the moral failures of humanity". == Reception ==