How do you get sister aceint blade?

To obtain the Sister Acient Blade in a game like "Xenoblade Chronicles," you typically need to complete specific quests or defeat certain enemies related to the blade's lore. Often, players are required to engage in battles or explore particular regions to find the blade's location. Additionally, you may need to fulfill certain character or affinity requirements to unlock the blade. Always check the game's guides or community forums for detailed steps specific to your version of the game.