Diana was sent to Coates Academy when her mother tripped and fell down the stairs, and she blamed her father for it, therefore sending him to jail. The police eventually realized she had tricked them and she was sent to Coates.
Diana went with Caine, Drake and Jack to Perdido Beach. She's one of the first to find out that Sam and Caine are twins. When Sam, Astrid and Little Pete are captured by Drake Merwin, she reads Astrid as barely a two bar.
Diana, Drake, Computer Jack, and Caine film Andrew taking 'the Poof' and are the first to discover the tempter. Before the Thanksgiving Battle, she sends Jack to go tell Sam about how to avoid the Poof, because she knows if Sam takes the Poof and leaves her with Drake, he will take out his hate on her, and she will eventually be killed. Her role in the battle itself is minor as her power doesn't really help her fight. Jack arrives too late, but Sam and Caine don't take the Poof, which allows her temporary fear of Drake to subside. After the fight, Astrid suggested her to join "Sam's side" but she refuses saying the bad girl always goes with the bad guy (Caine). It is hinted Diana has affection toward Caine yet doesn't seem to express it or any other emotion. Also, she tends to act emotion-less always ending up sounding heartless.
In Hunger, she's first shown to be taking care of Caine after he's come back from the Gaiaphage (Darkness). She asks him what the Gaiaphage is, but he doesn't tell her. The start of the book also tells readers that her rivalry with Drake is still going strong.
When Caine forms his plan, unknowingly to feed the Gaiaphage, Diana has to go in to town (Perdido Beach) to get Jack. To do this and not be recognized and potentially captured, she has to shave her head and pose as a boy. Jack recognizes her, but Dekka and Brianna don't recognize her, so the disguise serves its purpose.
Diana and Jack go to the Power Plant while in town, freak vs normal choas breaks out. At the Power Plant, Jack turns off the power in Perdido Beach (and the FAYZ) so Caine can try to bargain food (radiation) for light. Diana keeps telling Caine, that he can still change his mind, fearing that the radiation will kill them all. Sam points out that they're surrounded, and then Caine discovers he's feeding the Gaiaphage.
They escape and race to the mineshaft. On the way, Diana takes a shot at her nemesis, Drake, and Drake tries to kill her, throwing her head first into a rock. This leads to Caine killing Drake. Quinn arrives with a deeply injured Sam and he and Caine goes down into the mineshaft to find Lana. Lana heales Diana, and she gets to live for at least a few months without having to fear Drake.
Diana first appears when Caine walks in to her bedroom to tell her that Panda is dead. She hesitantly consumes Panda, with Caine and becomes a cannibal. She is shown as extremely sick, being much less attractive than she was before. Caine is the only one who is really taking care of her and he states she is one of the only two things he has in the world: Diana and the idea of the island that Bug told him about. Diana finds this hard to believe but shows no true attempt to stop Caine from leaving.
Diana is shown to be suicidal; she knows that she would not be accepted by Sam and the Perdido Beach kids, and so her only option is to stick with Caine and slowly starve to death. She no longer cares whether she lives or dies. When they reach the island, Caine and the others are tricked by Sanjit into eating some drugged food. Diana is the first to wake and she and Bug are the only ones who had not been tied up. She notices Sanjit attempting to escape with his adopted brothers and sisters in a helicopter, and knows that Caine will never let them live for tricking him. She therefore tries to kill him, but is stopped by Penny, who apparently is in love with Caine. Penny wakes Bug from giving him terrifing illucions, and he unties her. She then wakes Caine, siince she has also noticed the Brattle-Chances escaping.Diana begs Caine not to kill Sanjit and the other children, but he uses his telekinesis to hold the helicopter in place. He also makes Penny hover above the spinning rotor blades. In a final attempt to save Sanjit, Diana starts backing off the cliff they are standing on to scare Caine, listing the things she has done for Caine and revealing that she is in love with him. She accidently takes one step too far and falls off, but Caine releases the helicopter and Penny and saves her. Sanjit is starting to realize she tried to help him.
In Plague, Diana is still on the island with Caine, Bug, and Penny, where she tends to Penny's broken legs. Caine and Diana grow closer and share many intimate moments. When Diana asks him if he loves her he says that she's the only person he can't live without. They end up having sex. Quinn then arrives at the island with orders from Edilio to bring them back to Perdido Beach. Diana tells Caine that they should stay on the island but Caine can't resist the thought of being in charge of Perdido Beach. Penny, Diana, Bug, Caine, and Quinn all ride back to the mainland with the boat Quinn came on. Caine takes over Perdido Beach calling himself King Caine and saying that Diana will be his Queen. At the end of Plague, Diana and the rest of the survivors have the chance to either choose to go with Sam to Lake Tramonto or stay in Perdido Beach with Caine as their ruler. She chooses to go with Sam, with good reason, revealing to Sam, Dekka, and Brianna that she is pregnant with Caine's child, whom she believes had more powers than a normal baby, after realizing that the kid already has two bars and it was just two days since she and Caine had sex.
When Drake kills Howard, everyone is warned and safe. But what they don't know is that the gaiaphage wants Diana's baby so that he can be reborn. Drake was sent by the gaiaphage to bring Diana to it. Drake as Brittney walks at the bottom of the lake and crawls up into the boat that Diana shares with Roger, Justin and one of Justin's friends. Drake captures her by threatening to drown Justin if she does not come along. He takes Justin and Diana to the mine, whipping them if they are slowing him down to much.
When they reach the mine, Diana notices her baby is growing the whole way down. She is full term and is in labor when she reaches the Gaiaphage. Brianna comes and delivers the baby girl. Diana tells Brianna to run and make sure to keep the baby safe, but Penny makes an illusion of a hospital, with the Gaiaphage as a cradle, which Brianna lays the baby down in. The Gaiaphage takes control of the baby, but Diana is determined that her baby, who is named Gaia, is still inside.
Dianna carries the baby to Perdido Beach, trying to reach the barrier, and the baby keeps growing in her arms. After a while, they reach Sam, Quinn, Caine, and Astrid. Diana is concerned for her baby. They fight until they can hold off Sam and Caine long enough to reach the barrier. Gaia saves Caine's life at one point (who is hinted to have some control over the Gaiaphage) but still tries to take down the barrier and move on. Instead, the barrier is clear and the people on the outside can see everything that is happening on the inside, including Sam attempting to burn the baby, which runs off. The last we see of Diana is her running after her burning baby along with Drake.
In Light, Diana sticks with Gaia, who is still growing and never gets full. Drake gets sent off to find her something to eat, and Diana and Gaia see an adult climbing up the FAYZ wall on a ladder, to get a better view of the inside. Gaia hits Little Pete through her mind, and for a second the wall is gone and the adult, Alex falls through. Gaia rips of his arm and eats it. She asks Diana if she wants some of the now cooked arm, but Diana rejects, recognizing the smell from her low point of eating Panda's dead leg. Gaia heals Alex's bleeding shoulder after Diana's request. In the night time, when they are close by Lake Tramonto, Diana says that she has to pee, but instead runs towards the lake, warning that Gaia is coming.
She is one of the few people to survive the attack by Gaia and she walks to town with Astrid and a couple of the injured, to get healed. There she meets Caine and together they escape back to the island, after Caine tells her that he loves her and they share a kiss. On their way in the boat she tries to contact Little Pete, telling him to take over her body, like The Gaiaphage did to Gaia, since she has finally realized that Little Pete is the only one who can stop this. On the island they make love one last time.
When they come back to Perdido Beach with the missiles, Caine gets out of the boat with the missiles, but pushes the boat away with Diana in it. He confronts Diana about giving her body to Little Pete. Diana tells him that it does not matter, because Little Pete didn't take her offer, and Caine says it is because he got a better offer, revealing that he has also been contacting him. Caine uses his power to lift a devastated Diana out of the boat and bring her over to him. He says that he wrote two letters on the island. One of them was for her. A tearful Diana and a very calm Caine share their last kiss before Caine moves Diana back into the boat that is now floating many meters away from the mainland.
Diana jumps out of the boat into the water after Caine has left and meets Sam runing around lost in the burning town, looking for Astrid. They reach find Astrid at the "battlefield" were Caine has just been taken over by Little Pete. Diana runs towards him, but Edilio grabs her and pulls her away. The Gaiaphage gets killed, but kills Little Pete in the process and leaves the bodies of Gaia and Caine in ashes.
In the end, she is sent to a hospital in Santa Barbara with Astrid. Diana later receives a letter from Todd and Jennifer Brattle-Chance, the letter that Caine wrote apologizing for hurting her and telling her that he has always loved her, which she cries and laughs when reading over multiple times. Diana is invited to live with Sam and Astrid in LA, an offer which she accepts.
Her and Caine had a romantic relationship. Caine was in love with her, and the feelings were presumably returned. Diana was the only one capable of standing up to Caine; she called him out when she felt he went too far, and hers was the only opinion he really cared about. He is also the father of her child Gaia, who has the power to grow or ungrow any age she pleases.
Diana did not like Penny, finding her creepy. However, despite this, she still cared for Penny when her legs were broken, bringing her food and DVDs, along with helping her get into the bathtub.
Diana has a power, although it was considered weak by FAYZ standards. She is able to see how powerful someone else is- they use a system of bars, with one bar being the weakest, and four bars the strongest. The only two four bars are Sam Temple and Caine Soren. However, Little Pete was by far the strongest mutant. He was not read- but they estimated him to be somewhere around a ten bar.
Two days after conception, Gaia was already a two-bar, which worried Diana. Gaia is one of the most powerful entities in the FAYZ, along with Little Pete.
Early on, Diana used her power to test the threat that others posed. Most people were two or three bar, and Caine was the only four bar until she met Sam..
"Time to do the right thing. Even if it's for the wrong reason." - Diana (Gone)
"Bada bum bada bum bada bum bum bum." - Diana humming the William Tell Overture (Gone)
"Sadism. Enjoyment of another person's pain." - Diana "Words don't scare me." - Drake "You wouldn't be a psychopath if they did, Drake." - Diana (Gone)
"Oh, look, Drake's trying to think!" - Diana (Hunger)
"We're sitting in the dark, willing to sell our souls for another peppermint, with enough uranium to give a terrorist a wet dream." - Diana (Hunger)
"No, you sick stupid creep, I love you. I shouldn't. I shouldn't. You're sick inside, Caine, sick! But I love you." - Diana to Caine (Lies)
"Betray you? I've been with you every day, every hour, from the start of this nightmare!" - Diana (Lies)