When it came to Sigu Jian's life and death, the Shadow was more interested in it than anyone. He didn't want Sigu Jian to die by anyone else's hand, not even the heartless hands of god. Many years ago, there was suddenly a rebellion within Dongyi. Sigu Jian had come out with his sword and massacred all the elders and family in his clan. Only the 16-year-old Shadow managed to escape. Since then, his entire life has been lived with the purpose of getting revenge on his elder brother. He gradually sank into the powerful grasp of fear and anger and became the shadow behind two leaders of the Overwatch Council.
The reason Sigu Jian was known as an idiot probably had something to do with his crazed and overly bloody behavior when he killed the people of his clan.