Defeating Ultimaica
Ultimica is the end boss for this game. She has several stages and an aspect to the battle that makes it tough. I strongly suggest you read through all of this before fighting her, that means don't start reading this as you fight her. When you are preparing for the battle do it right outside her castle so you can save your preperations in case you die.
Preparing for the Battle
For this battle I like to use Rinoa, Squall, and Zell. You may have other characters but in this section I will refer to them as my favirote characters. Have Squall put the abilitys Auto-Haste, HP Bonuses, and Auto-Potion on. Make sure he has the command abilitys Revive, Recover, and Item on. Squall does not need to have any GFs on him except those that raise his stats. Have Rinoa put Auto-Protect, HP Bonuses, Str Bonuses. The command abilitys she needs are GF, Item, and Magic. Give her Doomtrain and make sure she has a healthy supply of Aura on. Give Zell HP Bonuses, Str Bonuses, and Auto-Potion. He needs th GF, Item, and Magic command abilitys. He needs Eden and also a healthy supply of Aura. Make sure they all have full health. Now climb the bell tower swing on the bell and go to the room with the gears in it. Follow the path out of that room. Climb down the two ladders. Walk down the hall and save at the save point. Again make sure your health is at full. Just to tell you a little about the battle, when one of your characters dies you must quickly revive them or a angel will launch them into time. She picks the characters she fights first so you want them to die. You must do this carefully. When one of your bad characters dies don't revive him/her. When the angel takes him/her away another character will come in. I suggest doing this until you have all you selected party members (the members you prepared for the battle.) Now is the chance for you to fight Omega Weapon. You hardly get anything from him not even a new GF. It is just a test to see if you can beat him. It is an optional battle, you do not have to fight him. Have your main party go up to the room near the chapel. Use the switch point. Have your secondary party go up the foyer to the right. Take the path down to the doorway and go into the room with a bell in it. Ring the bell and now you have 50 seconds to find him. Have your secondary party get to the switch point (fast.) Switch to your other party who should be waiting at the switch point near the chapel. Head into the chapel and Omega Weapon should be waiting there. Walk up to him and press X to start the battle. (Note: Omega has over 1,000,000 Hp.)
The Battle with Ultimica
If you beat Omega Weapon climb the clock tower, and if you didn't you should already be there. Walk into the room and the fight begins. Ultimica picks the three she wants to fight first as I explained earlier. This first stage is very easy. She can use triple on herself and cast tornado or malestrom. Just make sure you have your main party in for the next stage (I explained how to do this ealier in the preperations section.) Have Rinoa or Zell cast Aura on Squall and then get a Holy War on. Just use his limit on her several times and she should fall quickly.
The next stage is a little more tough. Griever has a solid defense against everything if the screen starts shaking and the sky looks differnt put a holy war on. Use Eden and Squall's Limit and this stage will die.
Now Ultimica will Junction herself to Griever. This part is tricky. Ultimica and Grivier can create Helixs that can attack you. Focus your attacks on Griever and Ultimica (they are junctioned so it is one person.) Don't worry about the Helixs.
This stage is when Grivier's tail and feet fall off and he is floating. Just do the same thing as last time and you will easily be able to fight the last stage.
This is the last stage. You need to have Aura (Squall) and a holy war on. Pummel her with your limits you need at least two Lion Hearts to kill her. Watch out for her Hell's Judgement attack which takes you Hp down to 1 and her Apocalypse attack which she usually dose after Hell's Judgement. (Note: Do not waste your Auras when you are in a holy war, it always misses so does all the othere status changes like haste, protect, etc...) In this case there are two parts to her one on top and one on bottom. The top one can draw from the bottom one. Just use limits, Eden, and Doomtrain to lower her defenses (you can also use meltdown.)When she dies you beat the game. There is a good long ending that is awesome and definetly watch the movie during the credits. Do not turn it off during the credits because after they are all gone there is another movie. That means 3 differnt movie scenes! I hope you all enjoy the great ending!