You need 2 Disgaea DS games and 2 Ds and a emtily save file foe both games
1.have a copy of you good save file in the 3rd save spot and play the copy file
2 go to trade items with you friend
3. trade a good item like yhe super robot suit on your coply file and your friend trades a weak iten.
4. how go too your good file not the copy and your copys this file and play the coply file and go to trade spot
5.trade item on your file and your friend trade your item you clone back too you
I wound do this too the super robot suit because it take a long time too refight ball in is demon form