Disgaea: Hour of Darkness

After defeating a monster it will show up in Character select. It will be selected only with lots of Mana. In order to get the Monster with little Mana, go where you can fight the Monster, and keep defeating him until its Mana cost drops to where
you can get it at your cost. Every time you defeat it go to Character select and watch the mana drop.

There is a simple trick to kill Uber Prinny Baal. You need a Scout or anyone with the Geo Change skill. Go to the Lord of Terror map, in Baal Castle, and have the person with Geo Change skill use it. If there are no "Damage 20%" or "Invincibility" Geo Panels, then hit "Quit" on the menu screen and try again. Keep Baal on the Damage 20% squares to have him die in 5 turns. Or, if you can do damage to him, wait for invincibility. It helps to steal Baal's items to do damage.

Speak to the skull in the shop, then speak behind the throne. Then her room will be in the corner of the next room where Ghoss and Gargo is.

Clear the Cave of Ordeals stage 5. Make sure you've unlocked it.

Enter the Item World B100 and defeat the Item God 2. If you exit, you must start over from B1.

No necessary Chapter: Make sure at least one of your characters has a spear mastery of 25 or higher. Enter the Dark Assembly, then speak to Longinus.

To unlock the majin class, you need each of the following classes, at level 200: warrior, male brawler, ninja, rogue, and scout. The majin is the best class in the game.

Speak to the Dimensional Gatekeeper.

Speak to Gargo.

Pass the Dark Congress proposal "Alternate Netherworld" to unlock the Alternate Netherworld.