We had a pretty cool concept for an additional sword with a somewhat different agenda, though Teggetto, the player, had to drop out before the game started.
The idea was a Knight of the Cross somewhere in the 12th century was slain in battle and in the process, Esperaccius was shattered. A Valkyrie had an interest in him and recruited him to the Einherjar, but since he dies simultaneously with Esperaccius, some part of the sword lingered in his soul when he was resurrected. When he later took up a sword and went into battle, the sword turned into the Echo of Esperaccius, as the remnants of the sword flowed from his soul into the new sword. The original Esperaccius had already been reforged at that time. Mechanically, it is pretty much the same thing, though it has more of an undercover agenda than the original swords.