Magic Edge

Note: On the Web Novel on chapters 6-30, 6-31, 6-34 it was called Magic Blade

Info
The light seems to be different depending on the amount of magic power you put intoWN 6-3.

This skill (although having it is not required) allows a person to pour their mana directly into their mana's to increase sturdiness and sharpness

Many different versions of this technique exist, each having a spell ability.

Trivia
In the Light Novels, it is called Spellblade.