Yin-Yang: Master of Equilibrium, Neutralization and Balance. Once, he was the teacher of both Princess Celestia and Princess Luna. He also is the ruler of Roanninshire, a underground city built somewhere in Equstria, and is the main headquarters of the Steed Knights of the Chess Table. Yin-Yang has the ability to split myself into two individual alicorns and to be merged again at will. His assistant is a spirit that can transfer himself form crystal ball to crystal ball named Foresight. He is friends with many great leaders, such as Neither Reach, Lord of the Underworld. His duty is to maintain balance between all that is good and evil. He always said that in order to understand the other side, you have to embrace it.  
Cutie Mark: Yin Yang Symbol
 
Nebula: A pony made up of cosmic energy and the wife of Yin-Yang. She would fly into space to restructure the cosmos and assures the universes remains in perfect harmony.
 
Aurora: Daughter of Yin-Yang and Nebula. She is made up of mystical light energy like her mother. She can sense positive feelings inside all creatures and enjoys the goodness in other ponies’ hearts, and is kind to those who deserve it. Aurora was made the ambassador of Roanninshire by her father, to negotiate peaceful terms in their affairs.
 
Shroud: Son of Yin-Yang and Nebula, and Aurora’s twin brother. He is made up of dark mystical energy and can create strange creatures out of his own essence. He can sense the little darkness inside a pony’s heart and would enjoy when those express their negative emotions. Shroud was made the general of Roanningshire’s soldiers, and to the Steed Knights. He is willing to take action when it is needed.