When running for Maplestory M Mesos DPS, Impact is vital. Its harm output is tremendous, and the extra effects a sigil gives it can squeeze out even more harm. Storm impact is highly suggested for the shorter cooldown but consider the elements still. The skill with the 2nd highest DPS output would be Echoing Blades, however, it requires your character to become static. Based on what you're combating, it can be beneficial to use or not. https://www.mmogo.com/Maplestory-m/Mesos.html