Is Grendel Evil?

In a world of chaos, he who lives, lives by his own laws and values. Who is to say that the death of millions is any worse or better, for that matter, than injuring a cockroach. And in the case of an existing power in the form of God, who is presumed to be all which is good, presiding and ruling an organized universe, why then does evil exist? The prosaic response of "without evil, there is no good" no longer holds any validity in this argument as the admitted goal of good is to reach an existence without evil. So even if a God does exist, I think it is fair, at this point, to say that he is the embodiment of both good and evil. And if humoring those who would answer the previous question with the response that there can be no good without evil, then can we assume that evil is simply a subsection of a defined good? Or perhaps even a good thing? If it is essential, those who chose the side of evil are simply abiding by good values. In the case of a world ruled by Chaos, evil is a non-existent word or value, rather. The system upon which a person's actions are judged also disappears leaving nothing but an instinct for natural survival as basic and primary as the life within the forests which we tear down to build our houses.

Ethics is a wide field of philosophical study to which the core of every question within falls to one side of a blurred line. On the right, is good; the value which is popularly believed to be the correct alignment for which a person should live their life according to. On the left, is evil; that which is the cause of most human misery, and prevents peace on earth. In John Gardner's book Grendel, the retelling of the ages old story Beowulf, further blurs the line between good and evil. Circumstance and perhaps a confused view of reality allow the monster, Grendel, to conceivably defend his evil beliefs. In order to better understand evil, using Grendel as a guide, I intend to attempt to justify it.
Grendel is born a neutral being,