That's simply an incredible mana advantage to provide any deck with
This rule means that a deck can have four copies of Zacian, four copies of Zacian V, and four copies of Zacian V-UNION in the same deck

#Ankou deck No.1203 Monster Saint Knight Ectodoma Squirrel Dogmatika Adin, the Enlightened Dogmatika Theo, the Iron Punch Noble Knight Custennin Noble Knight Medraut Noble Knight Iyvanne Noble Knight Borz Noble Knight Pellinore Infernoble Knight Oliver Infernoble Knight Maugis Infernoble Knight Renaud Infernoble Knight Roland Sublimation Knight Infernoble Knight Astolfo Infernoble Knight Ogier Chain Knight magic "Infernoble Arms - Durendal" "Infernoble Arms - Joyeuse" "Infernoble Arms - Hauteclere" Heritage of the Chalice Noble Arms - Gallatin Noble Arms of Destiny Reinforcements Armed Forgings Supermagic Sword of Raptinus Magnum Shield Traps Horn of Olifant Extras Infernoble Knight Emperor Charles Infernoble Knight Captain Roland Infernoble Knight Captain Oliver Artorigus, King of the Noble Knights TG Hyper Librarian Hi-Speedroid Chanbara Castel, the Skyblaster Musketeer Primathmech Laplacian Gagaga Samurai Drill Driver Vespenato Isolde, Two Tales of the Noble Knights Thank you for your interest

He will explain the set that's called Adventures of the Forgotten Realms from a role-players view
Then, you protect them by countering your opponents removal spells with [c]Counterspell[/c]s, [c]Force of Negations[/c], and the like