Juvia is announced as a candidate for the S-Class exam. While not thrilled to be going up against Gray, she tries her best. A foul wind blows across the island though.... This covers up to the end of the Tenrou Island arc.
To Juvia's surprise, Makarov selects her as a candidate for Fairy Tail's S-Class exam. She initially does not want to participate because it would mean going up against Gray. It also meant she could not partner up with him. The only one without a partner, Lisanna comes forward and offers. Her claim being she was friends with the alternate Juvia when she lived in Edolas. Juvia has doubts and views her as another love rival.
They travel by boat to Tenrou Island, the site for their exam. A sacred island that only member of Fairy Tail be on. From the boat, Makarov gives them the rules for their first trial: to reach Tenrou Island and pick one of the eight paths. Each path would be different. They could end up fighting one of the other S-Class mages in the guild, another participant in the trial or be lucky and get the clear path. Juvia and Lisanna are unlucky enough to pick route D, which had Erza at the end of its path. It's a quick and one sided battle as Erza decides to wear her Sea Empress Armor to cancel out Juvia's magic. Its not long before both Juvia and Lisanna are defeated.
They head to the base camp after their defeat and chat with Erza and Mirajane for awhile. Missing Gray, Juvia decides to leave the base camp in search of him under the ruse that she was worried for Wendy. She had lost her trial but had not made it back to camp yet. Juvia was less then thrilled when Erza insisted on tagging along. It is here that everything changes. Looking for Wendy, they stumble upon an injured Levy who fled to find help. Her and Gajeel had come under attack by the dark guild Grimoire Heart. It is revealed that Grimoire Heart is preparing to attack the island so Erza lights a signal flare, canceling the exam due to danger.
They are soon approached by Meredy, a Grimoire Heart mage. Meredy reveals her guild's plan to awaken Zeref and create a world where non-Magic users cannot survive. As the battle begins, Juvia is surprised that Meredy's seemingly physical attack injured her, instead of passing through her water body. As Erza fights the young girl, Meredy starts naming off her kill list. Putting Juvia at a low 13th and Erza at 4th, the red haired mage is surprised when their master is only listed at 2nd. When asking who is first, Meredy's face turns to digust: The man she wanted to kill the most was Gray Fullbuster. Meredy instantly gets Juvia's attention, causing heavy rain to fall from the sky.
Juvia slowly rises to her feet, in a somewhat horror movie fashion. She lashes out quickly and easily at Meredy, desperate to protect Gray. Erza can only watch on in shock as Juvia is completly different then when she fought against her in the exam. She tells Erza to leave this to her and to find Wendy and Gray to which Erza obeys. With Meredy getting pummeled, she decides to pull out her secret weapon: Sensory Link. She links Juvia and Gray together so that when she hurts her, Gray will feel it as well. This only makes Juvia's resolution to beat her stronger however, so Meredy has to resort to something more risky: Linking all three of them. Now it didn't matter who died, Gray would die too either way
Meredy decides the quickest way to achieve vistory is to kill herself, thus killing Gray and Juvia. However, Juvia stops her by breaking her own leg. She is unwilling to kill Meredy, not just because of Gray but because she does not believe in killing. She pleads with Meredy that all three of them can live. It can end differently. She tries to kill herself again but Juvia reaches her and hugs her. Meredy hesitates and starts to think back on her time with Ultear. Juvia pleads with her again to live for the ones she loves. Breaking through to her, Meredy starts crying and deactivates the sensory link between the three of them.
As Azuma destroys the Tenrou tree, Meredy brings her to safety. It is here that Ultear find the two girls and decides to off Juvia. Meredy protests and before Ultear can finish the dead, the unconscious Juvia is saved by Gray. When she hears his voice, she wakes up and as Meredy takes off with Zeref's body, Gray orders to pursue her. Juvia takes off after the girl, crawling due to her broken leg. The two girls run into Zancrow he takes Zeref's body for himself. However Zeref reawakens and unleashes a type of magic on Zancrow, killing him. Meredy and Juvia are both knocked out.
With Grimoire Heart defeated, the Black Dragon Acnologia appears and begins destroying everything in sight. Her leg still badly injured, Juvia is carried away by Gray as Makarov fights the dragon. However, the guild quickly change their mind and come running back to his defense. They decide to hold hands in attempt to protect themselves. They manage to cast Fairy Sphere and the island completely vanishes, guild and all.