Raina

"Why are you here?" "For you and others like you. People with gifts, I'm waiting for what's inside to be revealed. The girl, Skye. What do you know about her? Where does she come from?" "Why do you care?" "Because inside, I believe she and I have something in common."

- Deathlok and Raina

Raina worked as the recruiter for the Centipede Project which was unbeknownst to her a HYDRA science group. She was arrested by Coulson's Team after the Ambush on Oakland Centipede Base and placed in a secret S.H.I.E.L.D. prison. During the S.H.I.E.L.D. Civil War she was freed from her prison on the orders of the leader of the Centipede Project, The Clairvoyant. Now freed, she began to work on the Centipede Project once more, this time focusing on developing a new version of GH.325. She succeeded and injected Garrett with it. After Garrett attempted to take over using Deathlok Super Soldiers, she left HYDRA and Centipede with Ian Quinn. She then visited Skye's Father, telling him that she knew where his daughter was.

Centipede
Raina worked for the Centipede Project, the scientific branch of HYDRA behind the Centipede process, mainly as a recruiter due to her persuasion skills.

She recruited Michael Peterson to be a test-subject for the Centipede process, and she kidnapped Chan Ho Yin in order to use his pyrokinetic talent to make the volatile Extremis elements safe. She used the the Theta Brain-Wave Frequency Machine on Agent Phil Coulson to make him remember how he was brought back to life. After Skye tracked Coulson down, she was arrested by S.H.I.E.L.D. and imprisoned. She escaped with the help of Grant Ward, HYDRA's mole inside Coulson's Team, and finally met the man behind Centipede, the HYDRA agent John Garrett, the Clairvoyant.

Hong Kong
"You need a simpler name. A more powerful name. A name like Scorch." "Scorch? Are you joking?" "Have you ever heard of Steve Rogers? No? But Captain America-- now he's on the news, on a lunch box, on a poster on the wall."

- Raina and Chan Ho Yin

Raina would later approach Miles Lydon and pay him a million dollars for the retrieval of information about a super-powered pyrokinetic, a Hong Kong native named Chan Ho Yin.

Raina approached Chan in Hong Kong, and after talking her way into his apartment, abducted him for her mysterious employers. Working with the doctor known only as "Debbie", who was attempting to stabilize the Extremis element of the Centipede Serum, Raina assisted in the harvesting of the fire-proof platelets in Chan's blood that kept his power from burning him alive. After getting what they needed from Chan, he was scheduled to have all of his blood drained from his body.

Before that happened, Chan escaped and confronted Raina and Debbie. Raina closed the elevator door that separated her and Debbie and escaped, saving herself, leaving Debbie to be incinerated by Chan.

Raina was later seen visiting a prisoner named Edison Po at the Havenworth Federal Penitentiary. She informed Po that with the stabilization of the Centipede Serum, "Stage One" of the project had been completed and that they were moving into "Stage Two". She then asked Po to contact someone known only as "The Clairvoyant" for their mutual employers for any insights he might have as to "Stage Three".

California
"Will you tell me what he's like?" "Never. The last person who tried to learn such things got a knife for it. I don't want to have to do that again, Raina. You have such pretty eyes." "I understand. You can't even whisper to me about him." "No, I can't."

- Raina and Edison Po, speaking about the Clairvoyant.

Soon after, Centipede arranged for Po's escape. Raina was next seen in Oakland, California, assisting Po and bringing him up to date on the project's progress. Raina inquired about the nature of the Clairvoyant to Po, who was adamant in not revealing any details about him.

Raina assisted Po in setting up an unsuccessful ambush on the S.H.I.E.L.D. unit under the command of agent Phil Coulson, where Po realized that Coulson and his mysterious return from the dead was the key to Centipede's plans. Later, at Po's direction, Raina kidnapped the son of S.H.I.E.L.D. trainee and Centipede test-subject Michael Peterson in order to bring about another confrontation.

At the meeting, Peterson betrayed Coulson to Raina in exchange for the safe return of his son. Raina escaped by helicopter with Coulson to a location in the Mojave desert.

The Mojave Desert
"You didn't just give your life, you gave up your chance at a normal one, at love. And she did love you, Agent Coulson." "How could you know that?" "Do you miss her? Dinners at the Richmond. Do you miss hearing her play? You didn't even have a chance to say goodbye." "I couldn't... I can't..." "She cried for days after S.H.I.E.L.D. told her you died. They shattered her heart with a lie, and now they're lying to you." "No. No they're not." "I know you don't want to believe it, but you can't tell me nothing makes you doubt, makes you wonder what happened in Tahiti."

- Raina and Phil Coulson, the former attempting to win the latter's trust. At the Centipede site in the Mojave Desert, Po worked on interrogating Coulson, using a Theta Brain-Wave Frequency Machine designed to unlock hidden memories, while Raina saw to the recovery of Michael Peterson, who survived an explosion set by Centipede back in Long Beach. This lasted until the Clairvoyant grew impatient with Po's progress and killed him, giving Raina the job of finding out Coulson's secrets.

Through persuasion and emotional manipulation regarding Coulson's former lover, Raina convinced Coulson to not resist and let the machine do its work. While Coulson was under the machine's influence, his team arrived to affect his rescue. Raina was incapacitated by Skye, and taken into S.H.I.E.L.D. custody.

That S.H.I.E.L.D. was able to take Raina into custody alive would indicate that she was not outfitted with a Backscatter X-Ray Eye Implant.

The Hunt for the Clairvoyant
Agent Skye asked Coulson if, during his time in the Mojave Desert, Raina mentioned the death of his father. Skye had found that information in Coulson's psychological profile; it was called "a defining moment" in Coulson's life. Correlating the two caused Coulson to realize that the Clairvoyant is a S.H.I.E.L.D. agent.

Arguing with agent Coulson about why Victoria Hand should be killed instead of sedated if she was the Clairvoyant, Agent John Garrett said that Coulson and Raina were both subjects of the Theta Brain-Wave Frequency Machine, a fact that Coulson revealed to no one. This knowledge led Coulson to realize that Garrett was the Clairvoyant.

S.H.I.E.L.D. Civil War
During the conflict between the S.H.I.E.L.D. remnant and HYDRA, Garrett organized Raina's release by sending Ward to retrieve her; he even included a new flower-print dress for her. Upon meeting with Garrett, and learning he was the one known as the Clairvoyant at a HYDRA base in Cuba, Raina was very disappointed to learn that Garrett was not actually clairvoyant. Garrett won Raina over by presenting her with G.H. drugs recovered from the Guest House, and asked her to move the Centipede project into "Phase Three". Raina was unable to make much headway, however, as Skye had encrypted the files on the drugs so that only she could access them. In response, Garrett sent Grant Ward to capture her. Raina also presented Ian Quinn to Garrett, and seemed to delight in Quinn's discomfort at the situation.

Further Disillusionment
Raina's scientists recreated GH.325, but they could only make one vial, which she presented to Garrett. When Deathlok asked her about her motives, she explained that she wanted to help special people achieve their potential. Then she witnessed as Garrett's body began to fail and Ward ordered her to leave as he helped Garrett's cybernetics take control. When Raina found information from Coulson's Team Hard Drive pertaining to Skye's past, she called Ward, because she was disappointed that Garrett only wanted the drug for his own survival. She told him about rumors she heard about monsters destroying a village in China and her belief that those monsters were Skye's parents. When Garrett's cybernetics failed because of Fitz's use of the EMP Joy Buzzer, he asked Raina to inject the drug into him so he wouldn't die and she watched as he was strengthened.

True Allegiance
After Raina lets him know that she was not allied with HYDRA, the Centipede Group or him, the enhanced John Garrett convinced her that he could answer the question that she wondered since hearing of the "Clairvoyant"; so she asked him, "What will I become?" As Raina and Quinn were leaving with the Gravitonium, Ward stopped her, but she told him that chasing Skye was more important. Eventually, Raina went to a guarded room where she showed a picture of Skye to a mysterious man and told him that she knows where his daughter is.

Trivia

 * A character called Raina appears in the comic books. She is a member of the Hauk'ka from the Savage Lands. This is referenced in episode 1.22: Beginning of the End when John Garrett tells Raina that they are "prehistoric creatures".
 * Over the course of the series Raina has had ten different outfits and all of the them, except her prison uniform, have been dresses with flowers on them.