Secret of Mana Cheats
Dual Mana Swords
This only works in the beginning of the game, and you cannot go back and do this.
Before Primm leaves your party at Gaia’s Navel, make sure she has the Sword equipped.
Before she rejoins your party in the Haunted Forest, equip Randi (or Popoi, but Randi makes a lot more sense to do this with) with the Sword. When Primm rejoins, both Randi and Primm will have the Sword equipped!
From this point on, DO NOT SWITCH THEM OUT TO OTHER WEAPONS or this is null and void. Both need to keep the Sword equipped, but you can use Popoi to cross gaps with the Whip or cut things down with the Axe.
When you finish the Pandora Ruins, use the chest glitch at Pandora Castle to obtain the maximum number of Sword Orbs (8). Simply grab the chest with the Sword Orb, immediately switch characters, and then dash out of the room. The chest will not count as opened, but you will keep the contents. Wash, rinse, and repeat.
When you have enough GP to upgrade the Sword to max level (which will be a while – be careful not to switch their weapons), you will have two Mana Sword wielders for the rest of the game!