To duplicate items and souls, you will need two players, Lengedary Heros Souls, and an item you drop from weapons to other souls. First, summon a black or blue phantom. Have the phantom drop the items you want to duplicate. Then have him quit the game by pressing the PS button. Summon him back and have him drop more items and have him quit again. He will keep the items which he dropped and you can collect the duplicated items. You can do this with Legendary Hero's and Soldiers Souls.