The Spider Undead is the Category Ace of Clubs Undead and the secondary antagonist in Kamen Rider Blade.
Kamen Rider Blade
The Spider Undead intentionally had himself sealed into the Change Spider card so the Peacock Undead could use him to complete Leangle. When Mutsuki used the Leangle Buckle, Spider began to takes over his body, using him to become more powerful for the Battle Fight. Spider eventually begins to have so much hold over Mutsuki that the Rider began to turn into the Undead himself. However, the Spider Undead was forced out from Leangle while attempting to assume his King Form by Noboru Shima. Spider was properly resealed by Mutsuki with the King Rouser.
Kamen Rider Blade: Missing Ace
The Spider Undead was unsealed by the Albino Joker, but was resealed later by Kamen Rider Garren Jack.