Aisin Gioro Yinzhen is the 4th Prince of Emperor Kangxi and Grand Imperial Concubine De. He has another blood brother, Aisin Gioro Yinti (14th Prince). However, in the famous princes' fight for the throne, Yinzhen was part of a different faction to his blood brother.
Yinzhen, along with Aisin Gioro Yinxiang (13th Prince), initially supported the Crown Prince for the throne succession fight but after the Crown Prince was deposed by Emperor Kangxi for the 2nd time and no successor was named, and after Aisin Gioro Yinsi (8th Prince)'s faction started to make their move and targeted him, he decided to enter the succession fight for himself.
(Source: MusicalVeggies at MyDramaList)
