The answers are:"On kin of Cain was the killing avenged by sovran God for slaughtered Abel.""of Cain awoke all that woful breed, Etins and elves and evil-spirits."
These two sections of the passage contain biblical allusions to the story of Cain and Abel. This story is found in the book of Genesis. Cain murdered his brother Abel because he became enraged when the Lord accepted Abel's offering. After doing that, Cain was exiled.