User blog comment:DeathGodPrayer/Talk About What You Want!/@comment-24098614-20131220121842/@comment-1359322-20131220125158

No it's created through alchemy in DxD.


 * “Even though there are numerous holy-swords originating from all over the world, I still think the most famous one would be Excalibur. Even in Japan, it comes up in many books. It’s a holy weapon that is created through means of magic and alchemy by those who reach the territory of God. But holy-swords choose their wielders. I hear that only one person in a decade or so gets chosen.”

Remember DxD has it's own mythology system.