Disgaea: Hour of Darkness

Etnas Diary:
First go to the throne room and go behind the throne and flip the switch then go to the store place and press X near the skull and flip that switch, then go to the room in between the two rooms and go to the corner to the top left of the screen and press X in it and etna should say something like " I'm going to the bathroom, Okay" and it will take you in a room with a small menu in it. click one of the things in the menu and it will bring up a message from Etna's Diary.
If you visit this room during every chapter you are supposed to get a special item in the last chapter but i am not sure about that yet...

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

Instant Level Gain:
message: After defeating Overlord in (Chapter 6 - Writhing Shadow) go back to it, and there you will fight a Blue Dragon. If you have a Character or Monster you wish to level up, let them take the last hit to destroy Dragon, and they will go up one level each time it is defeated. Do this to each Character you want leveled up.