After you visit the Realm of the Almighty, you learn that you must extinguish the evil in Gittingham Palace.
Enter the Palace
After you land in front of the blue tree in the Gittish Empire, go north until you reach Gittingham Palace. After you bump into the evil barrier, Celestria will remove it for you. Go north to enter the palace.
When you arrive at the door of the palace, Lieutenant Hootingham-Gore appears. You have to fight him. There are two Bad Karmours with him. Hootingham-Gore can do two attacks per turn. Hootingham-Gore by himself is not very difficult, but the Bad Karmours can use things like Helm Splitter and Kabuff that can make things difficult. Each Bad Karmour has 188 HP and is weak to Earth and Light, and strong against Fire, Wind, and Blast attacks. Try getting rid of them first. As for Hootingham-Gore, use physical attacks on him because he casts Bounce on himself. His magic attacks are weak.
Explore the Palace
After you go inside the palace, go to the left. Follow the path around and you will reach some stairs. Go up, then go southwest and go through the door. Walk along the path outside and you will reach a chest that contains a mini medal. Then go back the way you came until you are indoors again. Go to the right and fall off of the edge of the red carpet. You will fall into the room with treasure chests. After you open them, go east and go up the stairs to the next floor. Check on the bookshelf to find the Secrets of the Sage book. The Supreme Sage gives you a quest that will unlock the Sage vocation. Afterward, go downstairs and go east until you reach two chests. Open them, then look for an opening in the west wall in this same room. Go through that opening and you will be outside.
Follow the path and go into the door at the end. Go east. You find a chest that contains a Seed of Deftness. Go outside again and go west. Look for another door in the wall. Go in. Go west and through the arch to find a chest that contains a Dark Shield. Then go north to a door. Follow the path and you will see a blue light. Step into the light to heal your HP and MP. Then go up the stairs to the east.
Go to the west side of this room and check the bookshelf to learn some recipes. Then go back to the east side of the room, go up the stairs and check the books in the bookshelves. You will learn some more recipes. Go back down the stairs, then go east and go out the door in the east wall. Go east across the bridge, then go counterclockwise along the wall until you reach a chest. Open it to get a Seed of Skill. Now go clockwise until you reach a bridge that goes northwest. Cross it and go into the door.
Walk north to cross the bridge and go up the stairs. From there, go west and then counterclockwise around the room until you reach a red and blue chest. After you open them, go outside. Go to the stairs in the middle and go up. Talk to the guy in front of the door.
Goresby-Purrvis is weak to Wind, Blast, and Dark attacks, and is strong against Fire, Ice, and Light attacks. He does two attacks per turn. He can do an Upward Slice that knocks down the target and is likely to be a critical hit. He also does Multislash, but it doesn't cause much damage. As long as you are prepared for Goresby-Purrvis's critical hits, you should be able to defeat him without too much difficulty. Just make sure that if anyone in your party dies, you can revive him or her.
After you defeat Goresby-Purrvis, go into the door that he was guarding. Heal everybody up, then go north across the bridge. After the cutscene, go up the stairs, then go north and talk to Godwyn. You have to fight him.
In his first form, Godwyn has weak attacks and only 1970 HP. Just keep yourselves healed up while attacking him. He is weak to Wind and Light. He attacks with Kafrizz, but it's weak. He can cast Disruptive Wave, so it may be difficult to take advantage of any Fource spells that you try to use because Godwyn will keep removing their effects.
Godwyn's second form is harder to defeat. It has 3250 HP. This time, it is very weak to Light, weak to Fire and Wind, very strong against Dark, and strong against Ice and Earth. Again, Godwyn does two attacks per turn, and can use Kafrizz (much stronger now) and Disruptive Wave. He can also cast Kabuff and can spew forth a cloud of Inferno, which damages everybody.
After the battle, watch the cutscene. You have to free the Celestrian held captive here in Gittingham Palace. Leave the room and make your way downstairs. You will see the energy barrier disappear from the door on L2. Go around to that door. You can cast Safe Passage to walk across the damaging energy unharmed. Then go down the stairs. Talk to the priest there if you want to save the game. Then go down the stairs to enter the Oubliette.