Ironic
Zhao Sheng looking all over for Xu Lin manual and methods of war while declining Zhao clan teaching, yet he is not aware that Xu Lin learned it all from Zhao clan. He could have gotten the most perfect form of the art of war instead of Xu Lin incomplete version. He leave Zhao clan to understand the secret of every scripture yet by leaving he get less than what he would get had he stayed.
Ironic
Zhao Sheng looking all over for Xu Lin manual and methods of war while declining Zhao clan teaching, yet he is not aware that Xu Lin learned it all from Zhao clan. He could have gotten the most perfect form of the art of war instead of Xu Lin incomplete version. He leave Zhao clan to understand the secret office every scripture yet by leaving he get less than what he would get had he stayed.
There is no reason to believe that Xu Lin having the the title of the mastermind of tianxia (or somewhere along the line) and the only thing that is of value in his art of war to Zhao sheng being the "incomplete" Zhao manual.
If anything one can say that 8th had learnt enough from the Zhao and deem it not worth it