In Master Duel, they have their own dedicated secret pack called The Darkness Amuses
draw 1 card, and if you do, show it, then, if it is a "Flower Cardian" monster, you can take 1 "Flower Cardian" monster from your Deck, except "Flower Cardian Cherry Blossom", and either add it to your hand or Special Summon it
These are all Flip Effect Monsters, and demonstrate the very earliest Effect Monsters in Yu-Gi-Oh
Interestingly, the Mitsurugi deck, featuring a Ritual-focused strategy, is less than a year old, though its impact on the game is undeniable, explaining its rapid ascension to Legendary Deck status
You can only use each of the following effects of "Centur-Ion Legatia" once per turn