Holy Sword

The Holy Swords (聖剣 Seiken) are weapons infused with Holy power and are considered to be the ultimate weapons against Devils.

Summary
There are two types of Holy Swords in High School DxD:


 * 1) The first type of Holy Swords are the mass produced light swords used by exorcists to exorcise Devils. As the name suggests, these swords have blades made from pure light. They are the more basic of the two types.
 * 2) The second type of Holy Swords are the "true" Holy Swords wielded by legendary heroes, such as Excalibur and Durandal. Unlike the normal light swords, "true" Holy Swords requires humans with high amounts of the light element inside their body in order to wield them, as such only a few people in a decade or so get chosen.

The Sacred Gear Blade Blacksmith has the ability to create Holy Swords, however they are inferior to the real ones.

Abilities
As the Holy Sword uses holy power as its source, it is extremely powerful against Devils. Small scratches from Holy Swords are enough to cause lethal damage to Devils. However, only a select few with the inborn ability (stated to be a large amount of light attribute) have the capability to wield a "True" Holy Sword. Holy Swords that are broken can be reforged as long as the core is still intact, as shown in the case of Excalibur. It is also possible for two different Holy Swords to be fused into one, as in the case of Ex-Durandal.

Each Holy Sword has great offensive powers when compared against a normal sword. Especially those forged by the God of the Bible and the Kusanagi.

Holy Swords
These are the Holy Swords of legend.

Excalibur
Excalibur is one of the two Holy Swords wielded by the Legendary King of Britain, King Arthur Pendragon, of Camelot. It was broken in the war long ago and reforged into seven swords through alchemy. Three of the blades were each stored by the Catholic Church Headquarter Vatican, Protestant Church, and Eastern Orthodox Church.

In Volume 3 of the light novels, Kokabiel and his men stole an Excalibur from each Church. Shortly after stealing Irina's sword, the four stolen Excaliburs were temporarily fused into one by Valper Galilei. The fused Excalibur (wielded by Freed Sellzen) was broken by the combined forces of Yuuto's Sword of Betrayer and Xenovia's Durandal. The broken fragments were then retrieved by Irina back to the Church to be reforged. The Excalibur fragments under the Orthodox Church were later fused into the Durandal as "Control Parts" for Xenovia, who was still unable to fully master the Durandal, to help protect the Peace Treaty between the Angels, Devils and Fallen Angels from terrorists and outside forces.

Even shattered, the Excalibur Fragments were more powerful than the Holy Swords of Blade Blacksmith, or the Demon Swords of Sword Birth. Though they were less powerful than the Holy Demonic Swords of Sword Birth.

The known Excaliburs are Excalibur Destruction, Excalibur Mimic, Excalibur Rapidly, Excalibur Nightmare, Excalibur Transparency, Excalibur Blessing, and Excalibur Ruler. Currently all the Excalibur Swords are fused into the Durandal.

Durandal
Durandal is a Holy Sword that was previously wielded by the Paladin of the Holy Roman Emperor Charlamagne: Roland. Roland had used the sword to fight an army of 100,000 men. It is a Holy Sword that is said to be on par with the original Excalibur. It is a sword with destructive powers that cannot be compared. It is the main weapon of Xenovia; however due to the sword's immense strength as shown by Roland, she has yet to fully master it. The Durandal was later upgraded into the Ex-Durandal (エクスデュランダル Ekusu-Dyurandaru) by using the remaining Excalibur fragments which function in the form of a sheath. The Excalibur fragments can also be temporarily separated and materialized as additional swords for Xenovia's use. The Ex-Durandal was shattered in Volume 11 by Cao Cao, using one of the True Longinus' Seven Treasures, but was repaired and fully completed after gaining the final Excalibur fragment that was previously owned by Arthur Pendragon.

Ascalon
Ascalon is a Holy Sword previously wielded by Saint George, the Dragon-killing Saint. Unlike the other Holy Swords, Ascalon specializes in killing Dragons, and is named the Dragon Slayer (龍退治の剣（ドラゴンスレイヤ Doragon Sureiyā). It was passed on to Issei in Volume 4 by Archangel Michael as a sign of peace between the Three Factions. However, members of each faction had to use various spells, alchemy and powers to allow Issei to wield it without being damaged by the sword's Dragon Slayer attribute. The sword is usually stored in the Boosted Gear and can be summoned in battle. Issei, however, rarely uses the sword and mostly lends it to Xenovia during fights.

Caliburn
Caliburn, also known as Collbrande, is the other Holy Sword wielded by King Arthur. The Sword in the Stone known as the Holy King Sword (聖王剣 Seiōken). It is the most powerful Holy Sword to be created, possessing sharpness and destructive powers that surpasses even that of Excalibur and Durandal. It is currently owned by Arthur Pendragon, a descendant of the original King Arthur.

Ame no Murakumo no Tsurugi
Ame no Murakumo no Tsurugi (天叢雲剣, lit. "Sword of the Gathering Clouds of Heaven") is a Holy Sword that rivals the original Excalibur and Durandal. It is also known as the Kusanagi no Tsurugi ("Grass-Cutting Sword"). Unlike the other four Holy Swords, that are said to be forged by God, the Ame no Murakumo no Tsurugi was found inside the body of an eight-headed Dragon called the Yamata no Orochi. It appears in the short-story published on Dragon Magazine.

Trivia

 * Irina's family had possession of a Holy Sword during Irina's youth, though its identity is unknown as it does not resemble any of the known Holy Swords.