Universe One (ユニバースワン Yunibāsu Wan), also known as World Reconstruction Magic (世界再構築魔法 Sekai Sai Kōchiku Mahō), is a extremely powerful Caster Magic.
A type of Magic that enchants the very ground itself on a scale at least the size of Fiore. It causes a bright light to burst forth from the earth and engulf all caught in its area of effect. It manipulates the very geography of the ground itself reducing it to 1/20 of its size and randomly alters the landscape and switches any people along it. It's true purpose however, is to bring a certain individual to a certain place in an instant, as seen when Irene casted the spell to send Zeref to the Fairy Tail Guild where Fairy Heart is located. The Magic is powerful enough to function against the notoriously strong and resilient Acnologia, and even the Emperor himself was disturbed at the fact that Universe One was even cast in the first place, further hinting to its power. It has been noted, however, that this Magic needs time to be prepared, due to its magnificent power and ability to manipulate geography of that magnitude.