There is little to do in the Tree Palace. After the boss battle with Aegagropilon, it becomes Grand Palace.
Walkthrough[]
You know that big purple island in the lower-right corner of the map? Fly Flammie there. Previously, you could not enter because a strong force was pushing you back. That force is no more now, so you can enter. Inside, the characters will automatically run to the three people that are already inside: the Emperor and his generals. Sheex, who was the Dark Stalker from Tasnica, wants revenge for what you have done to him.
After the battle, go left-down-right-up to enter the stage room. Run up to the Mana Seed to seal it...but it is too late! The seal is melting, which means that the continent that is underneath you will rise...Dryad, the tree elemental, appears. She tells you that you must get the hell out of here, and Sprite encourages her to give the party her powers. Dryad says that her "Mana Magic" was sealed by Thanatos, though, meaning her help will be limited. After gaining her powers, the party will call Flammie and watch the Grand Palace rise from above.