theblindninja: The most important thing for a ninja to know is to have a “heart of an iron wal

theblindninja:

The most important thing for a ninja to know is to have a “heart of an iron wall that doesn’t move anything”.
And he must suppress his own selfishness and personality and serve the lord to carry out the operation.

At that time, one’s purpose is kept secret, and the ability to manipulate the heart of the enemy is required.