The Fang of Critias (Blue) [DLCS-EN058] Ultra Rare Match of the Millennium & Twisted Nightmares Each time your opponent activates

Each time your opponent activates a Spell Card

add 1 "lswarm" monster from your Deck to your hand

you can add 1 Level 4 LIGHT Machine-Type monster from your Deck to your hand

If The Sanctuary in the Sky is on your side of the field

The Fang of Critias (Blue) [DLCS-EN058] Ultra Rare Match of the Millennium & Twisted Nightmares Each time your opponent activatesSet: Dragons of Legend: The Complete Series Card type: Normal Spell Rarity: Ultra Rare (This card is also always treated as "Legendary Dragon Critias".) Send 1 Trap from your hand or field to the GY, that is listed on a Fusion Monster that can only be Special Summoned with "The Fang of Critias" (if that card is Set, reveal it), then Special Summon that Fusion Monster from your Extra Deck. You can only activate 1 "The Fang of Critias" per turn.