If you have any guides on quick leveling for really low level characters that would be nice. The new skill leveling mechanic is annoying me as well, given you need to spend mana to level it up rather than just getting as you use it... I get frustrated trying to kill stuff with healers when I should be using them to heal...
I'm sure I'm doing it all wrong >_<
If anybody posts any responses ill read them tomorrow, crashing for the night.
if all you are planning on doing is completing the story mode then a few abuses of the item world will do the trick (this works in all of the disgaeas after 1 for the record one didn't have hidden rooms so it's much more tedious to power level)
When I mentioned playing disgaea as a puzzle game it was in reference to abusing item world. Note: most of my time doing this was with disgaea 2 so things might be slightly off as it has been a while since I played 3, but in general it should apply.
optional step 1: obtain some Mr. gency exits, these will only matter if want to save your progress if you run into some bad luck. They can easily be obtained by clearing the 10th floor of a low level item.
Step 1: Get a move that pushes enemies around, in general the fist weapon's triple strike is best as it's quick to get, and cheap to use. there are plenty of other moves, and with other moves the chance for fail drops more, but with triple strike as long as the gate to the next level isn't put in a corner you should be ok.
optional step 2: get someone that has wings so they can move through enemy squares. it's not a must but it will help. In disgaea 2 I used Tink a lot, in 3 a simple moth moster will do the trick.
Step 3: save and then find your highest level and go into it, a 100+ enemy item is best, but if you don't have one you will ideally pick one up during this. Don't worry about fighting the enemies, this is now a puzzle game, the goal of which is to get into a Mystery Gates or next floor before the enemies get a turn to murder you.
step 4. check the level for a Mystery Gates, if there isn't one just make your way to the next floor portal. If there is an enemy on the portal use the move that moves enemies on it to clear the portal. I would also recommend checking for critical geo squares, as those are easy exp/items for killing things on them as a level 1 character can kill a level 9999 on a crit square if they hit.
step 5: repeat step 4 until you find a Mystery Gates with any luck the hidden room will contain a chest. not all hidden rooms are good and some will rock your world, but when you do get lucky you will have an item way more powerful than you should, the end result usually is enough for a single character to be able to clear all of story mode if you can get a piece of armor and a weapon.
Step 6: if you make it to floor 10 you will want to leave, I can't remember if disgaea 3 has innocent town like disgea 2 did... if it does you will want to go there as there are often free items lying around.
in general this method requires a little luck, but I find it to actually be an enjoyable puzzle game and a different way to play disgaea in general. at the very worst case you will level up your most powerful weapon which will help as well. I am sure there are other ways to get more powerful (disgaea 2 had the nekomata abuse that you could do to net a level 9999 character when you were level 15 or so lol) but it's my general powering up strat in disgaea games. I find it usually takes about 2 hours to go from the story battles are hard to being a god that walks through all of the story battles, at which time I tend to try do the story mode with other characters and if i am having trouble bring out my god character. I hope this helps, i am sure there is a better guide for this online that coverers alterations for the method for disgaea 3. 3 is the one I played the least because I couldn't wait for it and ended up playing disgaea 2 for 250 hours the month before 3 came out and burned myself out on disgaea for a bit lol... I am looking forward to playing it again on the vita though.