He is the real hero of the novel but does not figure among the 108 knights..
Having an unequalled reputation within the world of "lakes and rivers" -that means the universe of outlaws - he also enjoys the prestige of his official charge.
Chief ward of his village, he chased an evil spirits by transferring a stone pagoda set in the neighbouring village to his.
His taste and gifts for martial arts as well as his sense of justice make that he wellcomes in his palace all the outlaws and valiant knigths that ask for a refuge or a protection.

Chao Gai
the Heavenly King

The imperial authorities show respect and fear towards him and his wealthiness makes the rest.
Present in the very first chapters of the novel, he will be killed treatrously in one of the last and will be avenged by the Outlaws of the Marsh.
Till there, he will be the real chief of the outlaws, inspiring Song Jiang's respect and obedience of a son for his father.
He is the real founder of the gang whose story begins with his adventures with Wu Yong, Ruan brothers, Gong Sun Cheng and Liu Tang well known as the Birthday Presents that became a Beijing Opera theme.