Kuja sends Zidane to Oeilvert to get the Gulug Stone in his stead, as he is reluctant to carry out the feat himself due to the anti-magic barrier. Oeilvert becomes inaccessible in endgame. As an anti-magic field prevents visitors from casting magic inside the structure (the following commands are sealed: Wht Mag, Blk Mag, Summon, Sword Magic, and Blue Magic), a good party choice for Oeilvert aside of mandatory Zidane is to take Steiner, Freya, and Amarant as their skillsets aren't considered magical. The party in the Desert Palace will be made of the characters who aren't chosen for Oeilvert.