The Elemental Shrines

Enemies in this area: Earth Guardian (boss) <Eat: Earth Shake>
The Water Shrine is just to the south of you, so fly over it and press O to drop Dagger and Eiko off.  Next to be dropped off are Freya and Amarant.  Take them to the Fire Shrine, which can be found to the north of Esta Gaza.  Third, drop Steiner and Vivi at the Wind Shrine, southeast of Oeilvert.  Finally, Zidane and Quina will go to the Earth Shrine, southwest of the Desert Palace.  You will play as this pair, though the game will check in on the others from time to time.  Make sure you equipped good weapons, and then head into the shrine.
	Walls will rise, and you must jump when you see the ! icon.  This will happen twice in succession.  You will then see Eiko and Dagger jump out of the way of what appear to be boulders of ice.  Zidane is being careful, but his mind is partly on Dagger.
Place the mirror on the altar.  Apparently Freya and Amarant are doing the same.  All your characters will face Guardians of Terra simultaneously.  Zidane and Quina will fight the Earth Guardian.  Use Mighty Guard, and steal the Rubber Suit and Avenger if you can.  Use Twister on the guardian if you have it.  After defeating him, you will pick up everyone else.  The ship arrives just in time to save Dagger from having to answer a difficult question.  Amarant asks Zidane a hard question, too.
Form a party and head to the Shimmering Island.  It is southeast of Esto Gaza.