who did it?

I don't know. They all have a murderous glint in their eye when they look at their father.

The person who should be gone is right here

You said it right Ryo! He really deserves to die and I am so glad that he did. I would’ve killed him myself if no one already has.

Bunzo managed to make his three sons hate him in a way that would make them want him dead. Even Ryo the innocent man is wishing him to be gone. That man can’t be a father, why does he keep insulting their mother in front of them? Is it a joy for him or something? Whoever who killed the bastard shouldn’t go to jail.

as expected darkly reveting

Ryo , the sweetest of all ..... thoughts rhow will he change when he comes to know truth bhind his mother's death.