<P> Big A was the person who took over the "A" game from Mona Vanderwaal after she was admitted to Radley Sanitarium and revealed to be CeCe Drake . She had visited Mona in Radley and used her to get information about the Liars before taking over the game herself and had used Mona, Toby and Spencer to do her dirty work and sometimes went under the Red Coat disguise . Big A often hid out at a lair situated in Room A at an apartment building at Mayflower Hill and a mobile RV which was stolen but Toby gave it back to "A" in exchange for information about his mother's death . However, the Team was disbanded in the third - season finale and CeCe acted on her own with a few minions and an ally, who is Sara Harvey . It is revealed that Charlotte had been hiding out in the basement of the DiLaurentis house and drilled holes through the floor to spy on the family in her Red Coat disguise and shared the identity with Alison . Her disguise as Red Coat was exposed in the fourth season mid finale when Emily was trapped on a saw at Ravenswood and later got into a fight with Aria who discovered her identity and Charlotte later fell off a platform and escaped . In "A is for Answers" the Liars are under attack by "A" who shoots Ezra Fitz on the rooftop . However, in the fifth - season premiere, the shooter is revealed to be Shana Fring who attempted to kill Alison but was later shoved off a stage by Aria and died from the impact . After all of this, Charlotte fled to France under the Vivian Darkbloom identity to escape custody for Wilden's death but returned . In the series's 100 episode, Charlotte placed a bomb in the Cavanaugh house which detonated, signalling her return to Rosewood . In season five, CeCe breaks into the Vanderwaal home and kidnaps Mona just as she is about to tell the Liars that Alison is "A" and covers up her kidnapping as a homicide . She then brings Mona to the Dollhouse and tortures her and forces her to dress up and act like Alison . Just as the Liars are being brought to jail, CeCe kidnaps them and tortures them inside the Dollhouse . Inside, the Liars discover that Big "A" is named Charles DiLaurentis . CeCe / Charlotte reveals herself as "A" and tells her story; saying that she is transgender, was formerly known as Charles DiLaurentis, and became' A' because the Liars were happy that Alison was gone . She worked with Sara Harvey, who was the Black Widow and a decoy Red Coat, and was also responsible for the "death" of Alison and the death of Wilden, and after telling her story, she attempts suicide by jumping off Radley but is stopped . She is admitted to Welby State and her reign as "A" finally ends and stays in the psychiatric hospital for five years . When she is released, Charlotte is murdered by Mona Vanderwaal and her death causes the birth of "A.D.", the new Uber A. After her death, it is revealed that Noel Kahn was also working for Charlotte . It is also revealed that her birth mother is Jessica's twin, Mary Drake, and her birth father is Ted Wilson, while Spencer is her sister . </P> <P> Uber A also known as A.D. is the third major "A" to have tormented the Liars . In the show's series finale, Uber A's identity is revealed to be Alex Drake, Spencer's twin sister who was put up for adoption at birth . She desperately craves vengeance over the tragic passing of Charlotte DiLaurentis, who was her half - sister, and is trying to seek out the person responsible . Unlike Mona or Charlotte, Alex does not use any nicknames at first but instead signs their messages with emojis, which differentiates her from the A-Team . This causes Caleb to nickname her Amoji . However, in the sixth - season finale, she begins using the alias "A.D." and kidnaps Hanna, whom she believes is accountable for her sister's homicide . Hanna manages to escape Uber A's clutches and Alex goes after Alison, who the Liars suggested as guilty for her own cousin's murder . Uber A eventually finds out that Alison is innocent after searching her jacket . While Uber A does work on their own, she also works through a new "A-Team" of helpers, known to consist of Jenna Marshall, Sydney Driscoll, and Aria Montgomery, who are assisting them in completing the endgame . The series finale explains that Alex Drake was put up for adoption in exchange for a sum of money (for Mary), but then left at an orphanage by her adopted parents who were concerned for their image . She ran away from the orphanage at ten years old and eventually started working in a bar in London, where Wren Kingston mistook her for Spencer, revealing the existence of Alex's twin and Charlotte . Wren introduces Charlotte and Alex in an airport (just after Charlotte met Archer Dunhill) and they immediately connect, becoming very close in a short amount of time . After Charlotte is released from Welby, she tells Alex that she wishes to return to Rosewood and resume the game, but Alex says she shouldn't go unless she gets to come too, since she wants to meet Spencer . Charlotte says no and describes the Hastings as "toxic people" before leaving for Rosewood, where she was murdered by Mona . Alex is enraged and forces Wren to shoot her so that she looks exactly like Spencer and can successfully impersonate her . She then goes to Rosewood and picks up the game as "Uber A". Alex has made several appearances where she impersonates Spencer, including, but not limited to: The run in with Ezra at the airport where she introduced Wren, the kiss between "Spencer" and Toby just before the latter planned to leave Rosewood with Yvonne, and Hanna's "dream" where she "hallucinated" Spencer while A.D held her hostage . The latter was done so that Alex could find out whether Hanna was telling the truth about killing Charlotte . </P> <P> The A-Team is a group of anonymous characters that worked together as "A". The team would work under the orders of the "A" in charge, who has been Mona Vanderwaal, the original leader and founder and CeCe Drake, the second leader . Five years later, Alex Drake, also known as Uber A, assembles a team of their own . This team continues using the same name, though is also referred to as the "A.D. - Team". </P> <P> Sara was the right - hand woman to Charlotte and also revealed as an A-Team member halfway throughout the sixth season . Sara is revealed as a Red Coat and the Black Widow, hired to pose as a decoy whenever Charlotte couldn't sport the Red Coat disguise . She then became Charlotte's friend and ally in the "A" game and assisted her in most of her schemes . Sara was allegedly diagnosed with Stockholm Syndrome following Charlotte's arrest, but later discloses to Alison that she lied under oath, also admitting that she and Charlotte were in fact close friends and she felt as though they were sisters . Later, Sara was possibly enlisted by "A.D." to work with them . However, Sara was killed by Noel Kahn after she tried to reveal more than she should to Emily . </P>

Why is there an a team in pretty little liars
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