Caladbolg

is the magic sword of Fergus mac Róich.
 Also given the appellations of and , it is a high-power and wide-range attack that makes even destruction of the landscape possible. It is the natural enemy of Cú Chulainn due to him having a geas that makes it his duty to be defeated once by the sword so long as it is wielded by someone who is -born. It is the prototype of many magic and holy swords of later ages, including Excalibur Galatine, and thought to be the same sword as from Welsh Mythology, possibly making it the prototype of Excalibur as well. The sword changes appearance as Saber goes through Ascension, becoming more drill-like.
It is noted in legends that it activates as a sword of light, unleashing a "sword-shimmer" that "stretches from the magic sword like a rainbow", allowing it to cleanly slice off the top of hills at full power.
 He used it as such when taking out his rage at being unable to take his revenge, showing its fearsome power by slicing through the tops of three hills. Despite such usage, its true aspects when wielded as a Noble Phantasm are more pronounced towards landscape destruction. Described as a "no-questions-asked great attack that breaks the earth", the Heaven and Earth Sky Great Rotation, he plunges it into the earth and causes a great eruption around the enemy.
==Variations==
===Provisional===
 is a version utilized by Fergus mac Róich in his child form while attempting to learn how to utilize his own power.
===Caledfwlch Caladbolg===
 is a variation used by Fergus mac Róich in his child form.
===Caladbolg II===
 is a modified version of the original Caladbolg using Reinforcement. Its appearance differs from the original, with a narrower drill-blade and a hilt and handguard that resemble Excalibur's instead of the thick blade and green handle of Fergus's version. Archer encountered the original sword at some point during his life, adding it to the numerous Noble Phantasms stored in Unlimited Blade Works and allowing him to modify it to improve its function as an arrow and suit his fighting style. He projects it to be used as an arrow rather than a sword, with the improvements aimed to make use of it as an A-rank Broken Phantasm. He chants the first line of Unlimited Blade Works' incantation before firing it and, despite being renamed with the "II", he still only chants "Caladbolg" to activate it. During this process, the blade further twists, stretching and narrowing into a form more appropriate for shooting. When utilized as a close-combat weapon, he thrusts it to pierce his opponent.
The blade of the sword coils into a spiral that can penetrate any target by creating a twisting distortion in space when fired. When fired at Caster, it is powerful enough to easily break through her magical defenses simply as an aftereffect of it being purposely fired at an area far away from her. Shirou believes that, even if she had tried to teleport away from the attack, she would have simply been twisted along with the space as well. After being intercepted by Berserker, it creates a large explosion capable of razing a cemetery and engulfing it in flames. 
Image:Caladbolgarrow.jpg|Archer preparing to fire Caladbolg II
Image:Caladbolgfiring.jpg|Caladbolg II being fired as an arrow
Image:Caladbolgtrail.jpg|The spiraling trail left behind after Caladbolg II is fired
Image:CaladbolgCaster.jpg|Caladbolg II against Caster
Image:Caladbolgcemetary.jpg|Caladbolg II razing a cemetery after being deflected
===Caladbolg III===
 is a deteriorated version of Caladbolg II utilized by Chloe von Einzbern. Releasing its True Name strengthens it and allows it to pierce everything by twisting space.
===Fergus, My Love===
 is one of Medb's Noble Phantasms where she temporarily summons the magic sword Caladbolg, the Noble Phantasm of Fergus mac Róich. With a lovely swing, she releases the sword of a rainbow-like light, the Heaven and Earth Sky Great Rotation, as a ranged attack.Fate/Grand Order material III - Medb, p.234-243
===Fergus, My Good-Looking Brave===
 is a Noble Phantasm of Medb in her swimsuit.
Employing the magic sword Caladbolg (the Noble Phantasm of the hero Fergus, one of her lovers in her previous life) as a weapon. She can perform the release of True Name as if a matter of course, but it seems that she is demonstrating some self-restraint at this occasion. Even Queen Medb - no, exactly because she is Queen Medb that there is no way she would cause an earthquake in a wonderful resort spot.
Nobody knows if, just like when she is a Rider, she materialized this due to the properties of her anecdotes and legends about "taking possession of heroes" or if she simply borrowed it from the Fergus at Chaldea.
As expected, its power have decreased compared to when Fergus himself uses it, but its flexibility, adaptability have improved in exchange. A rainbow veil is instantly deployed just by shaking it cutely with a "hey".
Enemy soldiers that become Medb's targets will probably be arrested in a rainbow veil and rendered powerless inside that light of ecstasy, without understanding a thing about what happened.
Her weapon of choice in this work. Release of True Name is not performed.
==Development==
Hirokazu Koyama is the weapon designer for Caladbolg II.
Gilgamesh is shown using Caladbolg from the Gate of Babylon on Lancer in the Fate route of the Fate/stay night anime, but it uses the design of Caladbolg II due to being developed before the original Caladbolg appeared in Fate/Grand Order.
==References==
vi:Caladbolg
Category:Noble Phantasms
Category:Anti-Army Noble Phantasms
Category:A+ rank Noble Phantasms
Category:A++ rank Noble Phantasms
Category:Swords
Category:Noble Phantasms introduced in Fate/stay night
Category:Noble Phantasms in Gate of Babylon