We don’t know what happened to Cain after he killed his brother Abel, did he go on to kill more people? Did he learn his lesson through a life removed from the presence of God? Which murderer was he at the end of his days?  All we know is that God gave him time and chance.Genesis 4, James 1:21, Nehemiah 9, Ecclesiastes 9

For scriptural references you can read this blog here: https://namibiancornerstone.com/i-am-cain-2/