Bonus Boss Battle:
After completing the Gate Generator and having Rudy rejoin the party, go to Saint Centaur and talk to the blind girl in the building under the Lone Paula Statue. The blind girl will tell you about a swordsman who had been frequently visiting her during the past few days. After this, leave the city and a message will notify you of a strange laughter. When it says “Do you wish to Continue?”, choose yes. After a little cutscene, you’ll be in a bonus boss fight againts “Monster Zed”.
Near the end of game, return to the Adlehyde sewers and bomb the floor in one of the new rooms.
Near the end of game, go to Baskar and talk to the guard by a pedestal. Proceed to the pedestal then head to Surf village. Then go to Jane’s house.
Defeat Monster Zed and bring him a Defense Unit from Malduke after halfway through that dungeon.
Leviathan (Water Golem):
Repair the Sweet Candy and sail in the water at the center of Filgaia.
After defeating Boomerang in Ka Dingel, go to Devil’s Playground and complete all 3 difficulties.
Barbados (Earth Golem):
After getting the Airship, fly northeast to a stretched land of desert. Land in the back area then ride on Asgard to cross over to the other side.