The Forn Álfur (フォルンアールヴ) or Ancient Elf, referred also as Koyomazoku (古妖魔族) in Japanese, is one of the oldest races. As such, they have high capability in using ancient runes. They aren't as common as Álfur or Nótt Álfur. An exclusive characteristic of them is that they live longer than other types of Álfur and keep a youthful appearance even when they become considerably old.
"Forn Álfur" means "Ancient Elf" in Icelandic.