Dynamis (神域 or デュナミス Dyunamisu) is the place where Z/X Extra cards are placed. It is a separate deck from the player's own deck. In the story, it is the name of the place where the Dingir lived.
Player may put up to 10 cards in his or her own Dynamis. The rule that states that you may only have up to 4 cards with the same name in a deck still applies to Dynamis. During a game, Dynamis is put into the field in face-down position. However, a player is allowed to look at the contents of his or her own Dynamis during the game.
Z/X Encyclopedia Entry
The place where the gods lived. It is isolated from the present world, and they can't interfere with each other. However, the conflict of the five worlds caused distortion in the time and space...... And the gods finally descended.
At the same time as the advent of the gods, different structures and landscapes rises above the sky over the Black Points. Because of that, there is a rumor flying around some Z/X users that the Black Point is the so-called product of god created with technologies from the Dynamis. However, the physicist specialized in many-worlds interpretation, Carl Wyvern, who has not yet encountered the gods is skeptical about the rumor.
"Dynamis" or "Dunamis" (δύναμις) is the Greek word for "power", "strength", or "ability". The base kanji for Dynamis (神域 Shin'iki) means "sacred area" or "sanctuary", a reference to Dynamis being the living place of the Dingir as well as place for Z/X Extra cards in general.