In the 2nd half of the game, find Cyan and sleep in Doma Castle, in the dream when your in the train, youll find the Genji Glove relic, which lets you hold 2 weapons for 2 attacks. Then travel using Figaro Castle until you get to Ancient Castle, go to the 2 doors to the left of the main entrance and open the chest, defeat Samurai Soul and recieve the Master's Scroll relic, allowing 4 attacks. Give the Genji Glove and Masters Scroll to Cyan, Sabin, or another hard-hitting character, and they will be able to perform 8 attacks, 4 for each weapon!