Youkai (妖戒; Youkai) is a family premiered in BS31, exclusively Yellow. Youkai cards are based off creatures and sprites from Japanese folklore. It is also the first family to have Spirit cards that can also treat themselves as Magic cards. During the God-King era, the family also includes western spirits and monsters, including vampires and the Frankenstein's monster. In God Advent era, the only Youkai card is Fuurin X; and in Ultra Advent era the family partners with the Evil Shadow family to support The Grandwalker Tsukuyomi in a spam-based deck.
In the anime, Hanzou Hyakki is the main user of this family.
On the collaboration side, the evolution line of Renamon from the Digimon series is in this family.