Continue your way through, you’ll have to walk a long way though. The enemies here shouldn’t be much of a problem since you’ve dealt with them before. You will eventually reach a save point, then head up and after the ghost talks with you. The enemies in here are tough…watch for the Defender Z, run if you must. Wait until a save point to fight these enemies. I suggest you just level up like a…well, like crazy. It’s not neccessary but a stat boost here and there can really help you along the way.
You’ll come across an intersection with the ghost of Seymour and his mother. Afterwards take the right path and pick up a Friend Sphere(yay!), and later on a Lvl.3 Key Sphere(finally!). To get the Lvl.3 Key Sphere you must look for a path that descends down…it’s basically near where the two tracks are going in slightly opposite directions, to the bottom left of where you had witnessed the Auron event.
You’ll encounter yet another Cloister of Trials…>.< Step on the first glowing floor switch in front of you. Now step on the first three tiles on the right, but not the fourth one up top. Then step on the tile to the top left…this will make the room go bonkers…err…I guess that’s how I can describe it. Push the pedestal at the top left, remember to press X, then head into the next room. Now this room is a little more difficult. Step on the 1 below to see which switch to step on. The map below is obviously not in proportion due to the text size, and I would change the text size but it would alter the guide in an ugly way. 16 rows across, 17 columns down.
After beating the puzzle, take the Besaid Sphere and place it on the right middle pedestal in the previous room. Then take the Kilika Sphere and place it on the last pedestal in the previous room. As the save point appears, save your game and continue onto the next room.
This battle will involve more strategy than brute. There are six glyphs that the party can move to. Use your summons only for Overdrives…they won’t be able to escape the Glyph mines. Use the CTB window(top right, the bars) and check the bar. If it gets almost dark purple(or whatever dark color, depending on your contrast), switch glyphs. Before you begin to attack, move characters in a triangle formation, so that when he strikes multiple glyphs, he will only damage one character. This boss primarily will just counterattack, but cast Protect and Haste(or Hastaga). Look for the Glyphs to glow, if it emits a ray and your character is underneath, move. It’s not too important that you wear Berserk Ward and Berserkproof equipment, but it might help. It doesn’t neccessarily hurt to have Auron in berserk mode…assuming his HP doesn’t deplete. If you can use all of your Aeons’ Overdrives, you stand an excellent chance of winning. Bahamut should do at least 11000 HP of damage now.
After the battle you’ll witness a series of shocking events. Be sure to save your game. If you need to unlock Lvl.2 and Lvl.3 Key Spheres, then fight the Defender Z, they will always drop one of the two…with Lvl.3 being the rarer one. Level up and be sure to wear equipment that protects against status effects like Darkness, Silence, Death, Confuse, etc. You probably won’t protect against all status effects.
Don’t use your Overdrives for the first form, save them. Attack like normal, having Yuna heal and cast Protect and Shell. Have Tidus cast Hastega. Her evade rate is somewhat high, so you might have a couple of misses in the battle. She’ll counter attack each physical attack with Blind and each magic attack with Silence…so make sure you have armor than protects against it or at least cure those status ailments immediately. Take this time to cast protective spells and such, and keep your HP up. Her absorb attack will drain close to 2200 HP. Keep in mind that when she does her little attack where it seems that ice comes off…she just removed your barriers. Now when the second form comes to shape, she’ll inflict Zombie status on all characters. This poses major problems as you will need to heal. Quickly heal your Zombie status and Yunalesca will cast curative spells on you. However, her Mega Death attack kills all…so being in Zombie status will counter that. You can Threaten Yunalesca, but if Auron is your most powerful member(which I am betting he is), then you should just stick with him attacking unless someone else has Threaten to freeze up Yunalesca…and hopefully prevent her from using Hell Biter. Use Blizzaga if you have it. Unfortunately for you she just keeps using Hell Biter…so you’ll either need to finish her off real quickly or keep a lot of Holy Waters and Remedies in stock. Your best bet is to dispose of her quickly.
When her 3rd form appears she’ll use Mega Death to kill all…so anyone not in Zombie Status will be killed. She’ll continue to use Hell Biter in this battle as well. Use your Aeons’ Overdrives now…they might not last long, but they should only be intended to use their Overdrives. Yunalesca will just cast Osmose and Drain on your Aeons, so you won’t be able to heal them and they’ll be low on life. Your Aeons will also be inflicted the Curse status, which prevents using another Overdrive. You may stand a good chance with Shiva in, assuming she can use her Diamond Dust first and then use her Heavenly Strike. The Heavenly Strike will sometimes freeze Yunalesca…allowing you to get in consecutive hits. But you’d be a lucky bird if you were able to consecutively damage her until the battle is over with Heavenly Strike. If you don’t have any Holy Waters or Remedies to heal the Zombie status, then kill the character quickly and hope that you can revie them.
Try to damage Yunalesca down to about 13000 and hopefully your Bahamut will do about 11000+ to Overkill her, this gives you a whopping 21000 AP instead of 14000 AP. Avoid keep all three characters out of Zombie form, otherwise when Mega Death hits, you won’t be able to revive. When you do revive, use a Phoenix Down only, no Mega Phoenix. If you do, you kill the zombie character and leave the other revived character(s) open to Mega Death. The key to winning this battle is to save your summons for the 3rd form if you can, then use them all(with Bahamut last) on the 3rd form. So I’m assuming you already have all Overdrives filled…otherwise they’d be almost useless. After the battle head back and then talk with Auron. You’ll soon learn a shocking truth about Auron.