Ozzie's Fort (ビネガーのやかた "Binegā no Yakata"?) is a location in Chrono Trigger that appears in 600 A.D. Here, Ozzie the Great, Diva Flea, and Super Slash are fought. Secondary home of the Mystics prior to the Mystic War, it resides in the approximate location of Fiendlord's Keep.
After Magus abandons his post as lord of Fiends, Ozzie resides at his own castle, named Ozzie's Fort, and now renames himself Great Ozzie. When Crono's party and Magus arrive there, Ozzie greets them and is surprised at seeing him with Crono's party and calls him a traitor. Ozzie then disappears and sends out Flea and Slash after them, both of which are also surprised to see Magus with Crono's party.
As they go through the castle's floors, Ozzie sends various obstacles at them, though they are easily bypassed. When he is at a dead-end, he, Slash, and Flea fight the party together. Ozzie tells Magus that he used him to create a world for fiends, though Magus tells him he only sought power. Ozzie then says he can not lose and has another barrier like the one he had in the Fiendlord's Keep surround him. The party again attacks some chains. This results in trap doors appearing underneath them, and they fall a floor below and make their way back up to Ozzie.
Once they reach the floor Ozzie is on again, a single Cat enters the room and hits a switch, resulting in a trap door appearing below Ozzie. He falls through the trap door and is never seen again.