Blade Bug

Blade Bug (剣刀蟲) is a special insect found both within YGGDRASIL and the New World.

Appearance
A large mantis flying insect creature.

Abilities
The Blade Bug can be used as a melee weapon when it attaches itself to the back of the user’s hand. When it wraps around its user's arm, it can shape shaped like a broadsword.

Trivia

 * The Light Novel never indicated that the Blade Bug was an aerial insect, but in the Anime it is.