I would say "A summary restates the same information in a different way, whereas a paraphrase only restates the main ideas." Look in my answered questions - there was a similar question asked. There you will find definitions.
Answer:
Grendel's mother and the Anglo-Saxons believe in the philosophy of taking "an eye for an eye."
Just like any other mother, Grendel's mother would do anything to protect her son.
The Anglo-Saxons understood that "sacrifice" would be a part of" victory."
Explanation:
Grendel's mother is described as an avenger, who wants to take revenge for the death of her son, with the death of the one who killed her son, even if it meant sacrificing her life. This shows that Grendel's mother, although a showy creature was an Anglo-Saxon mother and culture, a mother sacrifices herself for her son, as sacrifice is a victory in this culture and shows a strong commitment and courage.
Furthermore, revenge is based on the "eye for an eye and tooth for a tooth" philosophy showing that if you killed someone, you must die too.
I think it is called a paradox. A paradox is when something seems to contradict itself, but is actually a correct statement. Think of the song "Paradox" from Pirates of Penzance, it is all about an incident that seems to be false yet is true!
The introduction comes first.