The Deidad (ˈdeɪɪtɪ, Spanish: Deities) are a group of Shinigami that were alive centuries ago in the land of Soul Society. They have survived and are alive today. The Deidad consist of extremely powerful Shinigami that rival and in some cases surpass that of a Vasto Lorde and are in the arc set 20 years after the death of Aizen. There are a total of 11 Deidad and currently not all of the Deidad have been identified or made an appearance. The new arc is called Bleach: Rise of the Deities! The arc is still on going and has not been completed.
From here on contain information that may spoil the story for you
List of known Deidads:
Kyojin Number 11 Deceased
Kuraishisu Number 10 Deceased
Yofun Number 09 Alive
Subayai Koroshiya Number 08 Deceased
Zenno Tetsujin Number unknown Alive
Keiji Number unknown Alive
Iseul Saito Number 07 Alive
List of known skills
The Deidad introduce a new ability to the Zanpakutou known as Sugiru Genkai. Kyojin states that it is the true final form of a Zanpakutou and that only those of a certain bloodline can master it completely.
Those not of the bloodline supposedly can use it but not to its fullest potential and is usually not as powerful. We see this when Kyojin debuts the move. The intentions of the Deidad are to acquire special artifacts which are scattered throughout the dimensions. The artifacts can supposedly bend time among other things to the users will. Yamamoto stated that it was used in ancient times and a great war occurred over control of it.