The General planned to kill the American prisoner by sending his personal assassins and then removing his body from Sadao's house. The plan was not executed because the General forgot his promise to send the assassins.
The old General had a long expressionless face, which seemed to reflect the cold and calculated ruthlessness of the man as a General. He had an unusual sense of humour and seemed to generate fear in the hearts of others quite effortlessly. In his interaction with Sadao, he came across as a man who puts his self-interest above everything else. As Sadao was the only person whom he trusted with his operation, he lets Sadao off the hook. His cold and calculating streak was manifested in the meticulousness with which he latched out the plan of executing the American prisoner of war whom Sadao had given refuge.