Dance Ball at Balsamico Castle

Dance Ball at Balsamico Castle is an anime-only event that took place during the Key of the Starry Sky arc.

Prologue
Natsu and the others decide to accept a job to capture Velveno, a criminal who people thought to be coming in the Magic Dance Ball to steal a prcious ring that belongs to the Balsamico Family. The Fairy Tail members join the dance ball to capture him.

Dance Ball
Erza, Lucy, Wendy, Natsu, Gray and Elfman blend with the guests to capture Velveno while Warren, Happy and Carla observe from the outside of the castle using surveillance lacrima. Erza and Lucy are asked out by two men who looks suspicious. Warren tells Natsu and Gray to check the girls' partners but are interrupted by two ugly women who dance with them. A woman asks Elfman to dance with her which Elfman accepts gladly, making the exceeds suspect the beautiful woman for asking Elfman to dance with her and that if she is Velveno, she probably intends to drain Elfman's Beast Soul power. Natsu and Gray throw their partners away and go towards the woman. Warren commands Elfman to let Gray dance with the woman instead but Elfman denies. Natsu pushes Elfman away from the woman, and Gray dances with her. Gray asks the woman what kind of magic she uses but the woman tells that he should tell what kind of magic he uses first but Gray denies. The woman then shows her Ice-Make magic to Gray and the two start fighting but Erza stops them. Aceto comes out with his father and asks Erza to dance with her, which Erza accepts. Meanwhile, a young boy asks Wendy to dance with him which Wendy accepts. Carla states that it's nearly the time for the main event. The clock rings, and Aceto explains to Erza that the unveiling of the ring begins and that the giant clock only opens every 7 years and releases a device that displays the ring. The clock then opens and the Count states that whoever gets the ring has the right to propose to her daughter. While watching from the outside, Warren and the Exceeds see a mysterious thing in the lacrima, making them investigate about it. The Count then tells those men that would want to propose for her daughter should go for the ring. Warren, Happy and Carla find a tied up boy which states that Velveno grabbed him right before he came in. Warren then tells Wendy that the boy with him is Velveno making Wendy shocked. Velveno then transforms to his real form and attacks everybody with Wendy's Roar of the Sky Dragon, and takes the ring. Natsu then attacks Velveno but Velveno attacks with the same spells Natsu uses. Erza tells Velveno that she will be his opponent and commands Elfman and Gray to keep Aceto safe. Erza attacks Velveno but Velveno states that it's no use since he copied all of Fairy Tail mages' magic. Natsu states that it's alright and that he's still ready to fight a copy cat. Velveno tells Natsu that he didn't come to the castle to brawl with them. Velveno explains that he waited patiently for 7 years to propose to Aceto. He also states that Count's reasoning to take him away from Aceto almost made him give up with Aceto. Velveno then proposes to Aceto which she gladly says yes, making the Fairy Tail mages shocked. Aceto tells Velveno that he should turn himself in and pay for his crimes first before they get married which Velveno accepts.