Dream Dungeon Manager Dream Priestess:
There are several Dreamlands, but you never know beforehand to which one you are going to be teleported.
So it's useless to plan an attack on a certain boss monster.
Although if you go to the Dream Dungueon and kill a boss living there - no matter which one - your deed will bring balance to that Dreamland.
Remember their names: Gustav, Gustav Steward, Gabrielle, Gabrielle Minion, Ventus, Rekario, Tiat Baint. Please kill any one of them.