An alternate walkthrough of Mega Man X5's Sigma boss fight playing as Zero instead of X. You will need to defeat Sigma as Zero in order to access his ending. After this boss fight I realized that it's actually easier for Zero to defeat Sigma compared to X: it took me just a few attempts in fighting this boss although it's still not easy. The best contributor in winning this boss fight ironically does not involve any of Sigma's weaknesses, the Electric Blade and Twin Dream. Instead, this battle has been won by the Crescent Sword and double jump, the most versatile command art Zero learned in this game.