Episode 4: Metamorphosis is the fourth and final level of Resident Evil: Revelations 2.
Picking up after the duo have defeated the mutated Neil, we cut to Alex examining an encapsulated Natalia. Alex believes that Natalia will be perfect once she awakens in six months as a vessel for Alex's mind - looking over Natalia, she says that the life she has lived so far is only a prelude to her true birth (in Natalia's body). Natalia's body is moved deep below the tower. Meanwhile, Claire and Moira are taking the elevator to the top of the tower, aiming to seek answers about Alex (known to them as the Overseer) whom Claire decides to "put out of her misery". Arriving at the upper levels of the tower, the duo discover the computer station from which Alex has been watching their every move through hidden cameras. At the top of the tower Claire and Moira find and confront Alex, who now reveals to them that she wanted to surpass both Oswell and Albert Wesker in the pursuit for immortality. Holding the pair at gunpoint, Alex states that she must surpass her brother, but first must "escape" - she turns the gun on herself, and pulls the trigger. Alex's suicidal death self-destruct sequence of the tower, forcing Claire and Moira to run down the tower before it explodes. As they reach the edge of the tower, the floor above them starts to crumble. In an attempt to save her, Moira pushes Claire out of the way and is pinned out of reach by the falling concrete. With no other choice, Claire apologises to Moira and jumps from the edge of the tower into the sea far below.
After being knocked of a small cliff by Alex, Barry has a flashback showing that it was him who rescued Claire from the ocean. As she is being rushed into intensive care, he asks her about what happened to Moira. Claire apologizes to him, telling him that she wanted to save her; she is then taken by the doctors and Barry is left alone in the hospital, distraught over his daughter's fate.
After the flashback, Barry wakes up to see Natalia who has somehow forced the mutated Alex to flee. He asks her where Alex is and Natalia tells him that she went to the other side of the mountain. After dealing with the horrors below the mines and making their way through the underground research facility, the pair finally find themselves face to face with Alex, reciting the words of Kafka deep below the mountain. Driven mad that her attempt to kill herself failed and left her horribly mutated by the t-Phobos virus, Alex decides she has to kill the "other her" - Natalia. She injects herself with the remaining Uroboros sample, and further mutates into a horrible monster. Barry fights hard to protect Natalia and manages to seemingly incapacitate Alex, only to be knocked away and forced to watch as Natalia is grabbed and almost crushed to death by Alex. Suddenly, Alex is shot from above and drops Natalia. It is revealed that Moira is still alive, and has conquered her fear of guns in time to save the pair from Alex. Reunited with his daughter and Natalia, Barry leads the trio outside, only to find that he has led them to the edge of a cliff. Trapped between the hurt but still mutating Alex and the cliff's edge, there is seemingly no way for Barry, Moira and Natalia to escape. It is at this moment that a helicopter arrives, manned by a fully recovered Claire. Moira and Natalia join her onboard, but Barry decides that he has to finish Alex himself, and the fight with Alex continues on the edge of the mountain, though this time with air support from Claire. Alex manages to survive and continue chasing Barry until finally Claire shoots her in the chest with an RPG-7, completely destroying her. Back on board the chopper, Claire asks Barry what he's going to do now. He replies that he will go back to being a father, suggesting that Natalia will now become a true member of the Burton family. As the helicopter flies away, several choppers are seen going towards the island to perform a clean up operation.
After the credits there is a short scene in which Claire is driving on her way to the Burtons place while talking to someone on the phone. They inform her that her brother is in China - she tells them to tell Piers to take care of him. In the passenger seat is a large unknown gift that she supposedly wants to gift Natalia.
At the Burton's place everyone is getting ready and waiting for Claire except for Natalia, who is upstairs reading. News about bioterror is being broadcasted on TV about the C-Virus outbreak, indicating that Revelations 2 takes place before Resident Evil 6. As Moira calls out for her to come downstairs and greet Claire, we see Natalia who is reading a passage written by Kafka. Her choice of words, as well as her evil smile suggest that she is not Natalia, but in fact is Alex in Natalia's body.
If Moira didn't kill Neil with the pistol at the end of Episode 3, she will be crushed to death by the concrete during Episode 4, and Natalia will die at the hands of Alex in the final boss battle. She then revives and slices off Alex's hand, and kills her by pulling out her heart. Watching this, a shocked Barry asks Natalia "what she is" to which she replies that she isn't Natalia but is instead Alex - indicating that Alex's experiment succeeded and she was reborn in the body of Natalia. Natalia walks away while Barry warns her and tries to stop her, but is unable to bring himself to shoot at her due to their emotional bond. The game ends as Natalia walks away and Barry falls down in despair.
- Main article: Walkthrough:Revelations 2/Episode 4