He also finds out from Obi-Wan's Force spirit that Princess Leia Organa is his sister.
Reva knows that Anakin Skywalker is Darth Vader because she was one of his targets—a child—during the Order 66 killings that took place during the events of Star Wars Episode III: Revenge of the Sith.
Rey is Anakin's half sister, and Palpatines relations to Rey through the force. Rey is a genetic experiment/force experiment of immaculate conception orchestrated by palpatine. So Rey is Palpatines daughter or grand daughter, in a metaphorical sense. The same way Anakin is Palpatines son through the force.
It was common knowledge that Leia was adopted into the Royal Family of Alderaan, raised by Senator Bail Organa and the Queen of Alderaan. Kept secret was the fact that Leia was born to Anakin Skywalker, a Jedi who succumbed to the dark side and became Darth Vader.
In Return of the Jedi (1983), Leia helps in the operation to rescue Han from the crime lord Jabba the Hutt and is revealed to be Vader's daughter and the twin sister of Luke Skywalker.
The two became close friends, and recruited like-minded allies to prevent Palpatine's alarming grabs for power. At the end of the war, Bail Organa adopted Padmé's daughter Leia and raised her as an Alderaanian princess.
Padmé Amidala (portrayed by Natalie Portman) is the wife of Anakin Skywalker, the mother of Luke Skywalker and Leia Organa, the daughter-in-law of Shmi Skywalker, the mother-in-law of Han Solo, and the maternal grandmother of Ben Solo. She served as Queen of Naboo, and later as a Senator for her planet.
Darth Vader may have never known Princess Leia was his daughter in Star Wars and never cultivated a relationship with her, even when he was a Force ghost. Anakin Skywalker never knew Padmé was pregnant with twins, and he believed his child had died with his wife.
The Chosen One was revealed to be Anakin Skywalker, who conceived by the Force itself via the mystical one-celled organisms called midi-chlorians completely without outside influence.
Leia and Han had three children, and they named their youngest son Anakin after Anakin Skywalker, Leia's biological father. Since Luke was the twin to spend more time with Obi-Wan in the old canon, it made sense that he, not Leia, was the one to honor Obi-Wan when naming his child.
Rey was born on Hyperkarn in 15 ABY during the rise of the New Republic. Her father, Dathan, was a bioengineered Strand-Cast cloned from the genetic template of Darth Sidious, the Sith Lord who ruled the Galactic Empire as Emperor Palpatine.
Han Solo marries Princess Leia and they have three children: twins named Jacen and Jaina, and a younger son named Anakin. Luke reestablishes the Jedi Order, marries a non-movie (but fan favorite) redheaded Force-wielder named Mara Jade, and they have a son, Ben Skywalker (named in honor of Obi-Wan “Ben” Kenobi).
Master Yoda has risen above all others to claim the top spot as the most powerful Jedi of all time and the true chosen one according to IGN's audience. He won pretty handily as well, as he was victorious in 89,756 of his 95,243 battles and had a win percentage of 94.2%.
The Third Sister was at the Jedi Temple during Order 66. She either saw Anakin kill her fellow Jedi or saw the recording of his crimes. That's why she has such hatred for Obi-Wan. She was a Padawan who escaped Order 66.
Seething with ambition, Reva hunts down Jedi survivors of Order 66 as an Inquisitor. She wears the sleek armor of the secret order, and brandishes a unique lightsaber that can split in two to maximize her lethality.
In reality, she sought only to get close to the Sith Lord to kill him for revenge on his actions against her fellow younglings.
She was too well known for a start. The daughter {highly unlikely it was common knowledge she was actually adopted} of Bail Organa, a Princess of Alderaan and a Republic Ambassador. Pretty difficult for Obi Wan and Yoda to train her as a Jedi without it getting out.
Star Wars is finally exploring Leia's emotional reaction to the revelation Darth Vader was really her father - as her identity is transformed. Star Wars has finally revealed Princess Leia's reaction to learning Darth Vader was her father.
So, is Leia a Jedi? While Leia was just as strong with the Force as her brother Luke, she never became a Jedi. Still, she did begin her training. Shortly after the Battle of Endor, the twins began training together, with Luke guiding Leia through meditative practices and sparring exercises.
However, Leia's strong-mindedness during Vader's probe denied him the opportunity to discover she was his daughter. That serves to justify Vader's lack of awareness of his connection to Leia, although, perhaps, not as satisfyingly as if Lucas had planned for the relationship from the beginning.
Why didn't Darth Vader recognise Leia as his daughter in Star Wars: Episode IV? He didn't recognize her because he didn't know his daughter was alive, and he couldn't tell it from reading her mind because she wasn't aware of it herself.
He knows it's Anakin, and the events in this week's episode of The Clone Wars, "A Distant Echo," prove it. And I think Padmé is savvy enough of a political operator to let people think that Clovis could have been the person who fathered the child, if only to avert suspicion from her relationship with Anakin.
The marriage, witnessed by the droids C-3PO and R2-D2, was kept secret due to Amidala's place as a prominent Senator in the Galactic Republic and because of Skywalker's membership in the Jedi Order; the Jedi Code prevented Jedi from falling in love and forming attachments such as marriage.
The film doesn't flinch away from how horrific that act is, especially as it begins the downward spiral of Padme's death. Nonetheless, as she dies, Padme tells Obi-Wan that there is still good in Anakin. Even something as heinous as that couldn't fully break her love for Anakin.