Oga Tatsumi (Beelzebub)

Crying is the same thing as pouring all your frustrations and regrets out of your body. 
You may use it as a weapon, but that’s just too easy. 
Whenever you feel like crying, just smile instead. 
That’s what it means to be a man. 
You get it?

Gai Sensei

You put in so much effort, the operation will definitely succeed. For sure, the way to success will open.
Just in case... no, suppose the worst happened...
we will die together. Since I met you, my purpose has been to make sure that you become a great ninja.
  That's a promise.!!