Just as in Star Ocean: First Departure, you can obtain one of the toughest swords very early in the game by getting a decent level in Pick Pocketing (approximately level 6 to 8) and a Thief's Glove at Harly. Go to Mars Villag, and pick pocket the old man by the inn to get the Goodie Box. Then, go outside and save the game. Open the box and you will get three items. If the Sword of Marvels is not in it, try again by reloading your saved game. Eventually you will get this great sword and may not need to switch again until much later in the game.