After clearing the Labyrinth of Champions, the King will speak to you again. During this scene, you’ll obtain the Van Emblem and the Book of Techniques: Four Beasts SFT. Your main story mission now is to gather the Emblems from other kingdoms. For now, the party will rest for the night.
The next day, don’t leave the city yet. Return to the Castle to grab some items there. From the entrance, go to the right to reach the Armory. Pick up the Emerald Ring from the chest in the northwest corner of the room. If you go downstairs, you can go back to the Labyrinth of Champions to train, if you want.
Exit to the main hall then go to the left. Head to the second floor then continue heading to the right to reach the last room. Pick up a Magical Clay from the chest. Now you’re done for now in this city; exit the town (perform some PAs if you want) then make your way back to Eckdart.