Disgaea: Hour of Darkness/Episode IX: Captain Gordon, Defender of Earth

9-1: Valgipus IV
The nine enemies here are all aranged in a square formation. Using AOE attacks, your team should be able to take them out very quickly.

9-2: Thurvean Sector
On this map, there is a ring of geo panels surrounding your base panel. Nearby, there is a Geo Symbol with the No Entry attribute. On your first turn, throw all the enemies outside of the ring, then throw the Geo Symbol onto the ring. Now, the enemies will be unable to reach you but still posses some long ranged attacks. Use your longer ranged attacks to destroy them without taking damage.

9-3: Sphere VIII
On your first turn, move your characters onto the Geo Panels that gives +50% attack and +50% defense. The Brawlers wielding weapons are significantly more powerful than the ones without. Standing on the Geo Panels should equalize your strength fairly well. Stealing their weapons is another way to weaken them if you are having problems.

9-4: Cross Point
The map is covered with green Geo Panels this time. Since the only enemies you face here are spell casters, throw the Silence Geo Symbol onto the Geo Panels to prevent them from casting spells.

The enemies here all have 3 orbs equipped. There is very likely to be some legendary orbs here if you want them.

9-5: Primordial Soup
You will only be fighting two enemies here, so it is very easy. Focus on destroying Thursday first, as he has AOE attacks. repeat boss (level 38) gives around 36k exp.