The first order of business is to reequip all of your characters with their proper weapons if they still have their weakest weapon equipped from the visit to Ipsen’s Castle. You may want to return to Ipsen’s Castle with Quina as well to obtain the Blue Magic ability 
Doom from a Veteran (6,972 HP) enemy.
Other things you can do:
Catch more frogs for the Frog Catching side quest.
Take the new Kupo Nut back to Moguta in Gizamaluke’s Grotto for the Kupo Nut side quest; the reward is a random item.
Make sure that Quina is fully equipped with weapons and armor by switching Quina into your party if you need to. Quina will be assisting Zidane on his next mission.
Travel on the Hilda Garde III to each of the following locations using the pictures to help you…
The Water Shrine is located on the west side of the Forgotten Continent just south of Ipsen’s Castle.
The Fire Shrine is located on the northernmost section of the Lost Continent north of Esto Gaza.
The Wind Shrine is located on the southeast side of the Forgotten Continent southeast of Oeilvert.
The Earth Shrine is located on the eastern side of the Outer Continent near the Desert Palace but check the notes below before you enter the shrine itself.
Zidane gives you a hint that you and Quina should prepare for an upcoming battle. You can make the fight even easier by equipping Zidane and Quina equipment that protects against earth-based attacks. This includes 
Gaia Gear, using 
Reflect Ring to enable the 
Auto-Reflect ability and using the Devil Killer ability if either character has learned it.
Travel down the hallway and into the next room. When the room starts closing in on Zidane and Quina just press the 
Button when the Field Icon appears. Approach the pedestal and place the mirror in it to initiate the next boss fight.
Level: 54
HP: 20,756
Assuming Quina has obtained most of the Blue Magic abilities, you should make full use of each of them. Use Mighty Guard and White Wind to keep both Quina and Zidane fully healed up and protected and use Bad Breath to inflict a barrage of status effects onto Earth Guardian.
After all of the status effects have been inflicted you should have Zidane go to work attempting to steal the two items (
Avenger and 
Rubber Suit). The rest of the fight is fairly straightforward. Regular attacks to bring it down and items to heal up when your party member’s HP gets low.
Steal:
Avenger (common)
Rubber Suit (uncommon)
Drops:
Phoenix Pinion
A few cutscenes will take place after the battle involving all four of the teams at each of the shrines. Choose your team again at the end of the scenes.
The next destination is the Shimmering Islands on your way to Terra but there are some things you should take care of beforehand. This is your last chance to access many areas of the game on the third disc (and your last chance to complete the Cotton Robe Trick).
Most of the early side quests as many of the cities and towns will become unreachable after this point. The following side quests should be completed before you continue:
You should also make sure to pick up the following weapons which teach abilities as you cannot purchase them later in the game:
| Weapon | Ability Taught | Location |
|---|---|---|
 Mythril Sword |
Armor Break (Steiner) | Mimoza’s Mogshop (in Oeilvert) |
 Rune Blade |
Iai Strike (Steiner) | Daguerreo |
 Trident |
Luna (Freya) | Mimoza’s Mogshop |
 Heavy Lance |
Six Dragons (Freya) | Esto Gaza |
 Obelisk |
Cherry Blossom (Freya) | Daguerreo |
| Diamond Sword |
Power Break (Steiner) | Esto Gaza |
 Flame Saber |
Magic Break (Steiner) | Esto Gaza |
 Black Hood |
Death (Vivi) | Esto Gaza |
 Hamelin |
Jewel (Eiko) | Daguerreo or Esto Gaza |
 Octagon Rod |
Firaga Thundaga Blizzaga (Vivi) |
Daguerreo |
The next destination is the Shimmering Islands. They are located close to Esto Gaza on the Lost Continent and can be found by pulling up the map (or checking out the screenshot below).
There is some dialogue that takes place aboard the Hilda Garde III between the team members when you opt to enter and Zidane will get one last opportunity to either “Keep moving forward!” or select “Let’s pull back for now!”. Keep moving forward to move on to the next part of the story.
Zidane and the rest of the party will arrive in Terra and be treated by none other than Garland. You will have the option to select from all eight of your party members (with the exception of Zidane who is mandatory). Select your regular party and then head down to the lower right side of the screen.
Zidane will run into another humanoid creature on the next pathway - the Mysterious Girl in red. Take the stairs leading off to the left and down into the next screen.
Jump across the two ledges and open up the treasure chest to obtain a 
Coronet.
Jump off the platform heading north to find another treasure chest that contains a 
Dragon Wrist. Head back to the previous platform where Mysterious Girl appeared. Walk north into the next screen.
Grab the treasure chest on the left side of the screen to pick up an 
Elixir. Walk towards the Mysterious Girl in red again and she will run away once more. Continue across the bridge and through the next screen.
The next area has some spiderwebs on the right side of the screen that Zidane can use to climb down a level. Climb down one more level using the spider webs on the far-right side of the screen to reach a treasure chest that contains a 
Remedy.
Climb back up to the level above and head to the left side of the screen. Jump across the hole and open up the treasure chest on the far side to obtain a 
Mythril Racket and then climb down the last spider webs to the level below.
Open the last treasure chest to pick up a 
Demon’s Vest and then approach the Mysterious Girl in red. She will run off again down the bridge - follow her and once you reach her she will encourage Zidane to continue onward down the bridge.
There is a treasure chest that can be see on the left side of the screen as soon as you enter the next area. Travel up the stairs and go through the wall on the left side of the platform (shown in the screenshot below) and walk downward and to the back of the screen to find a secret pathway that leads down the the treasure chest.
Open it up to obtain a Minerva’s Plate. Continue up the stairs into the next area for another cutscene.
