Dynamis (神域 or デュナミス Dyunamisu) is the place where Z/X Extra, Shift, Event Extra, and the upper part of Z/X Overboost cards are placed. In the story, it is the name of the place where the Dingir lived.
Dynamis is a separate deck from the player's own deck. Player may put up to a total of 16 Z/X Extra, Shift, Event Extra, and/or upper part of Z/X Overboost cards in their 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 the game, Dynamis is put into the Dynamis Zone in face-down position. However, a player is allowed to look at the contents of their own Dynamis anytime during the game. All face-up cards in Dynamis can be seen by all player as well.
Z/X Encyclopedia Entry
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.
- Z/X Encyclopedia (Japanese)