Wanna use a deck master?

Before the start of the duel, each player selects one monster from their deck and banishes it. This monster is treated as the deck master. Then, each player creatively agrees on how that monster effects the field. After this, the duel starts.

Throughout the duel, durring either player's turn, you are allowed playing your deck master. This is not a special summon, nor does it count towards your normal summon or set that turn. When a deck master is removed from the field by an opponent's effect, without being destroyed, it is banished. If a deck master is removed from the field and is immediately replaced by a card effect, that monster becomes the new deck master and is banished instead of the monster. While the deck master is banished, it stays on top of the banished pile.

This duel ends when either a victory condition is met, a deck master is destroyed and can't be replaced, a player decks out, or a player runs out of life points.