when u firat do the cloister of trails there is an xtra hidden part do to, where u have to re-arrange the spheres, untill u get a treasure chest, u open it and a special symbol come out of the of the treasure cheast. The symbol correspond to the aeon ur about to get but worrie about a symbol when u get Bahamut. you get the last symbol is after u beat Lady Yunalesca. you leave Zanarkand then go back in to the room where u first light up the floor, there u only light up the white grids, once uve done that room go to the next room and light up the white grids in that room, then u should hear the hymp of the faith and then the wall will crumble up above the steps where the 2 spheres were and a chest will apear, open it and ull be able 2 get Anima, he is located where u first met the water monster but u have to beat him first.