Durandal is one of the four Holy Swords forged through the means of alchemy and magic, said to be on par with the original Excalibur. It is the primary weapon of Xenovia Quarta of the Occult Research Club.
According to legend, the original owner of the sword was the Paladin of the Holy Roman Emperor Charlemagne, Roland. Roland had used the sword to fight an army of 100,000 men, showcasing its immense strength, which is the reason why Xenovia had difficulties in fully mastering the sword.
Because of its great power and her lack of control over it, Xenovia keeps Durandal in another dimension for safety's sake. After becoming the Ex-Durandal, the offensive aura of the blade is harnessed or controlled by the sheath made from the Excalibur fragments.
The Durandal is a uniquely-shaped broadsword with a blue blade and a golden edge. The sword has a semicircular guard on the left side of the handle that extends to the bottom just above the pommel, with a small extension on the right side of the handle. Standing from the tip of the blade, the Durandal is slightly taller than Xenovia, surpassing the latter's height by just a few centimeters.
After being transformed into the Ex-Durandal, a large sheath surrounds the blade at all times, but can be retracted to allow melee fighting.
Durandal is a unique sword, to the point that it even responds to its wielder. For a wielder that seeks destruction like Xenovia, the Durandal releases a massive amount of aura with destructive powers. For a wielder that seeks precision like Yuuto, the aura releases a quiet hum and is easier to control. However, Yuuto still claims that the Durandal is like "a wild horse that needs to be tamed". The holy aura of the Durandal can also be used on other weapons, as shown by Xenovia when she uses it on Issei's Ascalon.
After being transformed into the Ex-Durandal by fusing the Excalibur fragments with Durandal, the sword also gained their abilities as well:
- Allows the wielder to cast illusions and manipulate dreams (Nightmare)
- Allows the wielder to transform the sword into any shape he/she desires (Mimic)
- Allows the blade and/or wielder to become invisible (Transparency)
- Grants the user and blade enhanced speed (Rapidly)
- Grants the ability to unleash overwhelming destructive force (Destruction)
- Amplify/strengthen the effects during a holy ritual (Blessing).
- Allows the user to control all things that he/she wishes (with the inclusion of Excalibur Ruler in Volume 12)
These powers can be accessed through the Ex-Durandal or by temporarily separating one of the Excalibur fragments to allow others to use that particular power or to allow Xenovia to wield with both hands. As of Volume 14, Xenovia has started to master the seven abilities of the Excaliburs. As of Volume 19, Xenovia has learned how to wield the full destructive power of Durandal by discarding any sense of control over the blade and having it absolutely eliminate everything in its path.
The Ex-Durandal (エクスデュランダル Ekusu-Dyurandaru) is an upgraded version of the Durandal, fused with the Excalibur fragments under the Church which function as a sheath. The Excalibur fragments can be materialized to be used as an additional sword. In Volume 11, the Ex-Durandal was shattered by Cao Cao's True Longinus. However, in Volume 12, the Ex-Durandal was repaired and fully completed after gaining all seven Excalibur fragments. It was said by Yuuto that upon mastering the Ex-Durandal, Xenovia would be able to use the special abilities of the individual Excalibur fragments, and would have enough skill to fight against Cao Cao's sub-species Balance Breaker on an equivalent level. Ex-Durandal can also be split into its original components, Durandal and True Excalibur. As of Volume 19, Xenovia wields Durandal separate from Excalibur in her original dual-sword style.
Durandal II (デュランダルII, Dyurandaru II) is an evolution of the Durandal Replica and the result of the Church's Holy Sword Research and was made so that Vasco could display his sword skill that was called a "miracle".
- The chant that Xenovia performs while summoning Durandal is a reference to the legend that says that the golden hilt of the sword contains one tooth of St. Peter, blood of St. Basil, hair of St. Denis, and a piece of the raiment of the Blessed Virgin Mary.
- Durandal or Durendal is derived from the French durer, meaning "to last" or "to endure".