Complete the indicated task to unlock the corresponding character.

Adell: Complete the "Demon Hall Mirror" stage in the Cave of Ordeals six times.
Marjoly: Reach rank 9 in the Dark Assembly, pass the "Mysterious Seal" bill, and complete all the stages.
Plenair: Complete the game, talk to Plenair, then choose the blank option
Priere: Reach rank 8 in the Dark Assembly, pass the "Alternate Netherworld", bill, and complete all the stages.
Rozalin: Complete the "Demon Hall Mirror" stage in the Cave of Ordeals seven times.
Zetta: Pass all the enemy bills, get Gordon into your party, then complete the first stage in "Stellar Graveyard" again.