Cain

Cain was the son of Adam and Eve and the brother of Abel. Cain was a farmer, while Abel was a shepherd. Cain murdered Abel due to jeolousy after God was satisfied with Abel's sacrifice, but rejected Cain's sacrifice. Abel's blood called out to God, but Cain asked, "Am I my brother's keeper?" God placed a mark on Cain's forehead and banished him to the land of Nod. (Genesis 4).

Some believe that the "daughters of men" mentioned in Genesis 6 were descendants of Cain.