Disgaea: Hour of Darkness

To capture an enemy, throw it onto the Base Panel. Then, the enemy fights against all of your remaining characters. The enemy will get some sort of boost, so its not too easy to capture. Humanoids and Bosses can not be caught. Use this to your advantage to capture strong enemies.

To have an easier time killing Baal, go to the map before Lord of Terror in Baal Castle. Capture a level 2500 Sert. Repeat a few times. Then, throw a Flamberg onto a Sert, and capture a level 3500 sert. repeat until you get a level 9999 sert. You will have to use the "Stronger Enemies" proposal about 10 times to get a level 9999 sert.

This will make killing Baal much easier.

There are two hidden switches in the castle. One is behind the throne, and another is near the skull on the counter of the Rosenqueen shops. Flip both of them to allow access to Etna's diary, which is in the middle corner of the intermediate hallway between the throne room and the shops. If you visit this area consistently for each chapter, you will be rewarded with a Testament item in the final chapter.

If you want to level up faster, just throw your enemies into each other, so they will combine into bigger enemies who are worth more experience points.

If you are trying to level all of your characters mainly by using team attacks, etc., move all your characters into position for a team attack. As long as none of them besides the initial attacker have not performed any actions, after the team attack
you can move them back to their original locations and move them again. Repeat this as desired. This also works if your characters are just out of a healers range; you can move them, heal them, then move them back into battle.

To get the Tyrant title for Laharl, beat Baal in Baal Castle.

To get Marjoly (Level 2500) to join your forces, beat her in the Beauty Castle.

To get Priere (Level 2000) to join your forces, beat her in the Alternate Netherworld.

Below are three great places to accumulate massive amounts of experience, thereby leveling up your characters more rapidly than usual.

Scorching Wind (7-1) - The whole field has a +100% experience bonus attached to it, and with tons of Zombies there, you’ll find leveling up to be rather easy here.

Forest of the Dead (11-1) - Another field with a +100% experience bonus attached to it, Mages and Pumpkins galore to kill.

Cave of Ordeals 3 - A field with +50% experience bonuses attached, but there are tons of enemies here, and they’re all bunched together, making for rather easy kills.

Once you open up the area "Cave of Ordeals". Go through it until you reach the 3rd area. Here you will find 3x3 rows of enemies and the field has a "Exp 50%" Geo panel on it. If you can use a 3x3 attack to kill all the enemies in this stage in one swoop, your character will level up insane amounts. You can take a level 1 character to level 200 if they have a high enough attack. Also be warned that the enemies in this stage have high defense, either bring out other members to weaken the monsters up or you can have one warrior bravehearted by a team of mages.