Carnwennan

The is a magical sword created and currently wielded by King Arthur.

Appearance
Carnwennan appears as a longsword with a square-shaped guard baring an Omega-like symbol. It has a wavy blade alike a Flamberg's, as well as a round pommel.

Abilities
Created with the power of Chaos, Carnwennan is able to instantly and completely regenerate its blade from any kind of damage.

Trivia

 * Carnwennan is named after the dagger of, used by King Arthur in the Welsh Arthurian legends, though in the manga is a sword rather than a dagger.