It's where you land after you've built all the Constructed decks you want to or when your life has changed to be less accommodating to playing a ton of Magic , like when you get a full-time job, have children, etc
A deck can have up to nine cards named Nazgul
Ifrit GREEN: Summon: Fat Chocobo, Chocobo Kick, Town Greeter, Balamb T-Rexaur, Goobbue Gardener OTHER: Adventurers Airship, World Map, Crossroads Village, any two-color Town Toms fate was sealed in 7th grade when his friend lent him a pile of commons to play Magic
You can exile it temporarily by discarding three cards, which can help protect it from lethal combat damage, removal, and lots of other horrible, no good, very bad situations