The Sealing of Deliora

 is an event which takes place during year X774 in which Ur sacrifices herself in order to seal Deliora, an evil Demon created by the Black Mage Zeref.

Prologue
Ur, Gray Fullbuster and Lyon Bastia are on their way home from shopping in a town when they overhear some travelers discussing Deliora's appearance in Brago. This alerts Gray as Deliora was the very beast who destroyed his hometown and caused his parents' death before. Motivated by his need for revenge, Gray sets out alone towards where Deliora is despite Ur's and Lyon's protests and arguments that he can't take on the monster. Ur threatens to expel him, but Gray ignores her and tells her that he'll blame her if he dies because she failed to teach him more powerful Magic. Later, Ur joins Gray and decides to take on the ferocious beast.

Sypnosis
Gray and Lyon are both defeated and unconscious. A desperate Ur tries to defeat Deliora but the beast seems to have the upperhand;Ur powerful spells are ineffective on the raging beast. Ur's legs have been replaced by an ice one due to the damage caused during the fight. Eventually, Gray regains consciousness and Ur tells him to take an unconscious Lyon and leave. She then tells Gray that she is happy to have them as disciples and that it is her job to take away Gray's darkness.

Ur unleashes her Magic and casts the infamous, Iced Shell. Gray watches Ur's body crack and transform as this Magic turns the user's body to ice for all eternity in order to seal Deliora. Before turning to ice completely, she asks Gray a favor; to tell Lyon she died because if he discovered she merely became ice, he'd spend the rest of his life trying to undo that spell. Ur tells that she wants both of them to see the world and live a great future. As Deliora becomes encased in ice, Ur seals away all of Gray's hatred and darkness.

Aftermath
Deliora is finally sealed, putting an end to its atrocities, and, Ur's body is transformed into ice for eternity.