Gae Bolg

Gae Bolg (ゲイボルグ) is a legendary demonic spear forged by Vulcan. He was destroyed by his brother, Durandal, and reincarnated as Hasta Ekstermi.

History
Gae Bolg is only depicted in a single flashback, in which he, having no user, is fighting Asras, who wields Durandal. A manic Gae Bolg barks at Asras's strength and wants to spill his blood, prompting Asras to label him a twisted soul not worthy of forgiveness. He then calls upon Durandal, who states he will slice through Gae Bolg's soul so that he cannot reincarnate, but Gae Bolg retaliates that he will slice through Durandal's soul. Although the outcome is not shown, it is later revealed that Durandal managed to destroy Gae Bolg, who reincarnated as the deranged Hasta. Gae Bolg is said to corrupt those who wield it, forcing them to slaughter needlessly.

In another flashback, Vulcan, having just forged Durandal, tells Durandal of his creation of Gae Bolg. He states that he once forged the world's most powerful spear with the ability to pierce anything. However, he claims that he was wrong and misunderstood the meaning of power, believing it to be a weapon's proficiency on the battlefield. Durandal wonders how the spear could possible be deemed a failure since a weapon's purpose is to slaughter, so Vulcan explains that a weapon's nature has nothing to do with its quality, which ignores the user. He then states that the spear went mad with the wrong kind of power—drunk with the blood of its users—and began taking the lives of both friend and foe. Vulcan comments that the spear was a failed product of misunderstood power created by a foolish smith. When Durandal asks what the spear is called, Vulcan replies with "Gae Bolg".

Trivia

 * Gae Bolg is based on the mythical Gáe Bulg, also a spear of pain and death.