Twin Wings Style

Twin Wings Style is the unique swordplay of Edelweiss.

Description
Twin Wings Style is a unique swordsmanship, developed by Edelweiss, the Twin Wings and Strongest Swordsman in the World, which lets one release invisible and fast slashes that has instant acceleration from the start. It allowed her to hold the complete advantage against another master swordsman, Ikki, despite his trained vision and using Ittou Shura at the same time, leaving him unable to catch a glimpse of either blade in motion; barely countering it through using Raikou multiple times.

It is later explained that it requires being able to move one's muscles in unison and mustering all of their strength at the same time, both in an instant. However, this requires one to control and change the nervous signals, which runs all across their nervous system themselves to achieve the instantaneous zero-to-hundred acceleration. It is a godly sword technique that converts their energy into attack power and speed, close to one-hundred percent of their potential, while producing no sound or vibrations in the air.

Aside from Edelweiss, Ikki managed to learn it using Blade Steal, resulting in an explosive growth, which allowed him to overpower the former Seven Star Sword King, Yuudai. Because of the Twin Wings Style, he could use his Seven Secret Swords without activating Ittou Shura. However, he couldn't use this sword style in the same way as its inventor, because of their difference in skills and preferences. During the Vermillion Empire Arc, he started adapting it to match him, thus making it his own original style instead of an imitation.

"Like Sara said, the difference between him and Edelweiss was vast. But… to say that they used the exact same techniques was wrong, obviously."

- Difference between styles.

Despite using the exact same sword style, outside the main difference in their sword skill: Edelweiss uses a Two-Sword Style, due to the nature of her Testament, her Twin Wings Style focuses on pure offense, shutting down all her opponents using a relentless barrage of strikes, while lessening the speed and power, because she focuses on wielding a sword in each hand. Ikki, on the other hand, uses One-Sword Style, due to the nature of Intetsu, it has lesser strikes, but because he wields one sword in both hands, it has greater power.

Weaknesses
Despite being arguably powerful swordsmanship but there are some notable weaknesses, the most notable being that due to the 0 to 100 speed, there's no way to stop after moving.

Trivia

 * In Light Novel Volume 08, Nene mentioned it also requires raising ones' metabolism and blood circulation.