Місоно Кай

Kai has long hair and is Shou's younger twin. He excels in his studies and is the representative chairman of the Misonou Combine. He seems untouchable and cold to other but he is actually quite caring to people close to him. At first, Kai wasn't sure he has a twin and ignores Shou. It turns out that long ago before the twins were separated, Shou had told Kai to totally forget him. Kai moved into a wealthy family and has forgotten Shou. When Shou mentions that he is his twin, Kai's memory was a little blurry. He is in a relationship with Nagi Uesugi and there are flashbacks that give hints of their relationship and they always been together after Shou and Kai were separated, he is also Nagi's "One and only".

Kai is also a white-winged member of the royal familyand prince of Winfield Kingdom. He is a "puppet" of the black-winged's leader, that is why he knows who Ran was. Kai went into berserk mode when Nagi was "killed". (from Wikipedia)