Assassin (Female Selke) - Appears on Hard or Very Hard only, world map, near Desert Ruins, must be in Multiplayer and have an extensive friends list.
Female Yuke - Must be at the end of the game on normal, talk and she hides out in the world map, on a patch of brown. Cast a spell where she is and talk to her.
Gerald (Male Clavat) - Appears on Hard or Very Hard only, world map near forest, must have 1,000 kills.
Male Lility - Appears near the beginning of the game on normal, must have 100 hours of play time.
Male Yuke - Appears near the end of the game on normal, must have every scratch card.
Nun (Female Clavat) - After completing Library 3 on Hard, find her in Library 1 and talk to her to unlock a quest. Complete the quest Monster Busters 2 and talk to her
Penguin (Female Lilty) - Appears on any Difficulty, in front of the Library, must be on Very Hard to recruit.
Red Mage (Male Selke) - Appears on any Difficulty, in front of the library, pay 5,000 Gil.
Rid Dek - Have over 100 hours gameplay. Find this character in the Town, in front of the Adventurer's Guild.
Boss Fight Mode
After all events of the Library, return to there and clear the enemies in the first area to reveal the warp point. This warp point leads to the room where you can fight the bosses in "Ring of Fates." Just put the book onto the bookstand to enter the fight.