Extra Classes:
Note that just having the mastery isnt enough you'll then have to petition the Dark Assembly with the appropriate bill to be able to create them.

Archer - Have someone with a level 5 bow mastery
Beast Tamer - Successfully capture a monster
Chaos Soldier - Finish the game once
Samurai - Have someone with a level 5 sword mastery
Gunner - Have someone with a level 5 gun mastery
Heavy Knight - Have someone with a level 3 spear mastery
Magic Knight - Have someone with a level 3 sword and staff mastery
Male Ninja - Have someone with a level 5 fist and sword mastery
Female Ninja - Have someone with a level 5 fist and staff mastery

Unlock Akutare Ending:
Get Defeated by Akutare

Unlock Bad Ending:
Have Adel 10+ Previous Offense, Killed Ally 50+ Times, Then Finish The Game

Unlock Etna Ending:
Defeat Etna in Chapter 3

Unlock Laharl Ending:
Defeat Laharl in Chapter 11

Unlock Middle Boss:
Ending Defeat Mid-Boss Before Chapter 4

Unlock Tink Ending:
Defeat Final Boss with Lvl. 1000 Tink

Unlock Worst:
Ending Have Adel 99+ Previous Offense, Killed Ally 99+ Times, and Rossary Formarly Dead