Christ prayed for His own persecutors. He came to forgive us of our sins, period. Not just for blasphemers, idolaters, sexual deviants, thieves, liars, slanderers, but also murderes.
Rudolf Höss confessed his sins to a priest, received absolution and Holy Communion, even publicly apologizing to God for his sins against others, embracing his earthly punishment. He had this to say shortly before his execution.
“My conscience compels me to make the following declaration. In the solitude of my prison cell I have come to the bitter recognition that I have sinned gravely against humanity. As Commandant of Auschwitz I was responsible for carrying out part of the cruel plans of the ‘Third Reich’ for human destruction. In so doing I have inflicted terrible wounds on humanity. I caused unspeakable suffering for the Polish people in particular. I am to pay for this with my life. May the Lord God forgive one day what I have done.”
This is how powerful God’s forgiveness and mercy are; He can save you even at a moment before death. Of course, it is still possible God made him undergo additional trials in Purgatory first. God is both merciful and just after all; He demands justice for sin. Yet we can see clearly how God’s mercy plays. It reminds us of Holy Writ’s words: “His mercy endures forever” (Psalm 136).