For: Carry on my wayward son.
When Yamamoto was 3 years old, he saw his mother been killed, and at the same time, he saw every man who killed her, be slashed by his father sword.
When he was 15, he discovers that he is walking the same path that his father was. So he tries not to kill, but protect.
When he completes 18, he discovers that to protect, sometimes, he has to kill. Because he is a mafioso now, and he can't pretend anymore.
"This is not a game" - Says Hayato one day, they are together on their bed, in their flat.
Yamamoto looks at him, and quietly replies: "I know...I know..." - and what he wants to say is: I already knew for a long, long time.
One day, when he reached his 20th birthday, and was expecting his father's congratulations and happy smiles, instead, he found him lying on the floor, blood everywhere at the tatame.
The men who did that, still there, looking at him with smiles on their faces, thinking they have the upper hand, because they surprised him.
But everything went blank.
When 'he' returns, they are in pieces.
He kneels down at his father's body, and he is breathing! So weak, and then, he says something, serene, so quietly low, that he have to put his ear next to his mouth. He listened, and he said: "Carry on, my wayward soon. There'll be peace when you are done..." and Yamamoto started crying, so hard, like when he was 3, and his mother was killed. So his father, with his last breath says: "Lay your weary head to rest...Don't you cry no more"