If he had time to use the hammer, it would have been better and more efficient as well. However, Rain still didn't hesitate in using all his mana to expand his forearm guards… instead of covering it in ice or earth, Rain just converted his raw mana into diamond blades.
When everyone saw that, they opened their eyes widely… they knew people who could use their earth magic well to the point that they could create gold, but not a diamond. Just a few grams would consume all of their mana… and here was Rain with two diamond blades.
"Bring it on, asshole," Rain said.
