Shizuku is heading for the main lab to find Marco and help him defeat Zeus and uncover Patient Zero, but unbeknownst to her, Marco is already dead, and Zeus's creatures, his Pantheon of Monsters, is searching for her to bring her to Zeus. She hides from them by ducking into the ductwork, but one of them is small enough to follow her, while the other goes after the Original Patient Zero, Alice.
But when Kasumi finds her way to the place where Marco tried to fight Zeus, Ron and Tim are already there. And so is Marco's dead body. Thanks to her shock and horror, she's caught, and taken down to confront Zeus. There, he taunts her, telling her that the monster that she sees in front of her *is* her sister, and that her condition as a monster is all Kasumi's fault, that it was her fault that her sister wanted to die.
Kasumi flashes back to her life at home with her sister, and remembers that after she and her sister became infected, they made a pact to live and die together. But Kasumi was naturally more depressive than her sister and didn't want to live without her, so she attempted to cut her own throat with a straight razor in the bath. Shizuku discovered her and stopped her before she could go through with it, and was very angry at Kasumi and refused to speak with her, which drove Kasumi even deeper towards depression.
And Kasumi realizes that he is speaking the truth, and that Shizuku's presence here is all her fault. Worse, he tells her that she has already had a reunion with her sister and doesn't even realize it- the giant monster that has birthed all the monsters around them is her sister- and Kasumi never even realized it. Kazumi is horrified and frightened by this truth, and begs Zeus to end her life, to let her find peace. But Zeus keeps right on taunting her, even as he points a gun at her and plans to kill her. And Tim and Ron are connected to the Shizuku-monster with vast pseudopods that nearly cover their heads
Above the Arena, Alice drags the remains of her body to Marco's, and uses the last of her life and the power of Medusa to bring him back to life. In the Afterlife, where death waits to take him across the tiver, Death asks him if he is ready to go. Marco thinks he is, and then he remembers Kasumi and tells death that no, he isn't ready to go yet. He still has something to do- he has to save Kasumi. Death tells him he is a fool, and the causeway he has walked to get there starts to crumble, but Marco runs back across and makes it to the portal, where Peter, Katherine and the Senator, all of whom died before him, tell him he has their love and support. (Well, the Senator just harrumphs, but he doesn't deny it).
Alice has disappeared. Not even the remains of her body is left, but Marco is alive, and he comes to Kasumi's aid. Zeus taunts him as well, telling him he's a fool for thinking the outcome this time will be any different, but Marco is able to disperse Zeus's body for a bit and tells Kasumi that her sister's pod is inside the monster's body. She has to meet and confront her sister and keep her from her rage. Kasumi agrees, and gets up inside the monster's mouth, and walks inside.
Down in the stomach, she sees Peter's original coldlsleep pod, and she walks towards it, only to be confronted by a Medusa Ghost of her sister telling her to keep back, and not to come any further, Kasumi talks to her, but she is also remembering. She and her sister finally made up on the day she was to come to the facility, and they stopped in a park to talk. But after she finally got her sister to forgive her, she proposed they leap off the cliff in front of them and seek death together, and her sister objected. There was a fight and...
Kasumi continues to walk forward, and finds a dead body on the ground in front of the pod. A dead body with a bandaged throat. Her throat should be bandadged. After all, she cut herself when she tried to commit suicide. But her throat is undamaged. Then, who is she? What is she? And how can she exist when her body is dead? As Kasumi tries to find answers, Marco, realizing that Zeus is just information, sees the one way that Zeus is vulnerable- he can be hacked. But can he do it before Zeus's monsters kill him? And can Kasumi live with the knowledge of who she is and what has become of her sister because of what she did? And what has happened in the outside world, and what will the survivors do to find out?
This was a shocking conclusion to the series. Yuji Iwahara has been playing with the readers all this time, playing with our lack of knowledge about the characters and what knowledge the readers have been given. All the time, we were assuming something- something that turns out not to be true. We do find the real villain of the piece, and although the Venus Group and Ivan Coral Vega set up the situation, it took Zeus to exploit it in a way that would have been very bad for everyone on earth.
Essentially, he wanted to be a god, and to play sick evolutionary games with humanity for his own personal amusement. He thought that Humanity had stopped evolving and growing stronger, and by torturing them with his monsters, he could force the growth he thought humanity needed. But when Kasumi went to confront Shizuku, he grew weaker, which gave Marco an opening to try and destroy him.
I found this entire series thought-provoking and affecting, and the ending is true to the nature and ideas behind the story, which makes the whole thing almost frighteningly good. Okay, it's sci-fi survival horror, and all the elements have been done before, but here they are combined and twisted in such a way that the whole becomes much more than the sum of its parts. In the end, there are only five survivors of the 160 patients in the facility, and only four survive as actual humans (Katherine becomes that harpy-like bird... thing). The series ends on a hopeful but cautionary note, and the rest remains untold. I wish I could say that I would love to read more, but this was a satisfying (in a story way) ending for me. Still Highly recommended.