In GF II he kills his own brother.
In GF III he does turn the reins over to Vincent, and I guess you could argue he was trying to become legitimate and realizes that the "legitimate" world is as corrpupt as the mob..."The higher up I go the crookeder it gets..." Even so, his first reaction to Don Tomassino's death is to tell Calo that he may be asking him for a favor.
"Io sono stanco, sono imbigliato, and I wan't everyone here to know, there ain't gonna be no trouble from me..Don Corleone..Cicc' a port!"
"I stood in the courtroom like a fool."
"I am Constanza: Lord of the idiots."
| 
