Excalibur (エクスカリバー, Ekusukaribā) is the obnoxious Great Old One and former member of the Eight Shinigami Legions.Predating the creation of the Demon Weapon race and serving as the inspiration that led to their creation, he is a Legendary Blade and is officially recognized as the most powerful weapon in the world.
As told by Franken Stein, Excalibur is the strongest weapon in the world, ranking even above the likes of Death Scythes. Despite his height in power, his power isn't on par with that of Asura, whom the former Warlord was describe to be more powerful then that of Excalibur (and the rest of the Eight Shinigami Legions).
As a Great Old One, it is assumed that Exclaibur possesses a powerful Wavelength to the point of being consider on a god level. In the anime, he was the only individual who was able to watch the likes of two Gods of Death, Death himself and the Kishin Asura, battle and unfazed by their power, unlike Death the Kid and Azusa.
Madness Wavelength (狂気の波長, Kyōki no hachō): Being a Great Old One, Excalibur is reputed to have a godly-level Madness Wavelngth on par with the likes of Kishin Asura. It is said by the Great Old One of Power that his very existence drives men to insanity.
- Madness of Anger (怒りの狂気, Ikari no kyōki): Nothing is known of the true nature of the Madness of Anger other than as the name suggest, those under the subject of this Madness is pulled into insanity in some shape or form relating to anger.
Transformation (変身, Henshin): Excalibur is capable of transformation due to being that of a Legendary Blade.
- Humanoid Form: In the anime, it is assumed that Excalibur is among the other Warlords in the Eight Guardians of Death in which all of other Warlords possess humanoid shapes.
- Holy Sword (聖剣, Seiken): The very presence of his transformation makes the air in the immediate vicinity vibrate and when its considerable powers are initially invoked, the surrounding area is bathed in a brilliant dazzling light.Enamored with strong, magical power, its wielders grow Wings of Light and gains the ability of instantaneous teleportation. In addition, each swing slices through space itself.The weapon is able to resonate with anyone and everyone, provided they're capable of bearing the obnoxious personality of Excalibur himself.
- Wings of Light (光の翼, Hikari no Tsubasa): A pair of bright golden wings are given to anyone who is wielding Excalibur, giving them the ability of flight at high and capable speeds. In addition to this, Excalibur is also shown to summon forth wings on his own Weapon form to fly independently.
- Holy Explosion (unnamed): Excalibur's ultimate move in Soul Eater: Battle Resonance. Excalibur transforms into his holy sword form, shooting himself downward onto the ground close to the opponent and releases a very powerful explosive wave.
- Teleportation (瞬間移動, Shunkanidō): Those wielding Excalibur can teleport instantly from location to another. The speed of the teleportation is instantaneous, as shown when Hero using Excalibur was capable of dodging Triple F (Flame Flit Fist) and Sanzu River Shot despite their incredible speeds.
Enhanced Agility: Despite his looks and demeanor, Excalibur possesses some sort of eccentric skill in avoiding attacks from multiple individuals. This is seen when he easily avoid the attempts of Spartoi members Kilik Rung, Black☆Star, and Patty Thompson, whom are among the most competent unarmed fighters within Spartoi and with the first two aforementioned being some of the DWMA's top students.
Autonomous Skill: Excalibur has the ability to not only be used by potential Meisters but also can utilize all of his skills he bestows onto other individuals himself, such as flying using the wings of light and pass through spatial rifts. However, he does so within his own weapon transformation.
Enhanced Durability: Excalibur is an extremely durable individual, able to survive a blast from Asura using Vajra without so much as a scratch, with these blast capable of downing even Death himself. However, due to the fact it was Death who took the full force of the blast at the time, it is unknown how much of his actions contributed to Excalibur surviving the blast.