there is no unlockable character in this episode.

Stoj:
you need to both beat the boss and open the door of both the valley archive and Lava Archive Floor 1.

Patty: To unlock Patty, you need to create and furnish the gathering place.

Rudy: To unlock Rudy, you need to unlock Patty first, then you need to get to the forgotten city wish is located on the map at 2 right, 1 up. Then you need to go to the shoreline wish is located at 4 right , 4 up. It is recommended but not necessary to level up your map level with trust.

Al and Mari: Go to the shoreline. it's located in the Celtic Field.

Seama: Go to the forgotten city. it's located in the Celtic Field. with her in the party, you can now create Seama items.

Klinsy and Neville: go to the Cathcart Forest, near the Tower side. return where the boss was, but do not take the exit. instead, go right, up and left, and you should see an animation.

Papelne and Patty, go to one of the tower after the bridge, the tower is located at 2:1

Rudy: after unlocking Papelne and Patty, return to the Shoreline.