Answer: Claudius. Claudius prays to God and in this state he finds Hamlet. This is a convenient case to kill Claudius, but Hamlet does not because during the prayer the soul of man is turned to God. If you kill Claudius now, his soul will go to heaven. He remembers how treacherous his father was killed: when he slept, he did not have time to think about anything, to repent of his sins, to be forgiven. In short, to be killed during prayer is too good a fate for Claudius-the king-brother-murderer and traitor.