Whoever battles with monsters had better see that it does not turn him into a monster." I think this means the same thing as when Socrates said he didn't want to go into politics because he was afraid it would corrupt him. Basically, if you spend your time battling evil in any form (corrupt people in business, greedy politicians, etc.) you have to be careful that you don't become what you hate.
A good example is the city councilor who goes in thinking that he's going to fix all the problems, but over time he starts accepting bribes and becomes corrupt. "And if you gaze long into an abyss, the abyss will gaze back into you." I personally interpret this to mean: if you dwell on questions or problems that are too big for you, it will take a toll on you.
Like if you spend all your time wondering what is the purpose of living, you might become discouraged and depressed, and forget to live at all. In this case, I think Nietzsche used "abyss" to mean something that we can't see or ... more.
I cant really gove you an answer,but what I can give you is a way to a solution, that is you have to find the anglde that you relate to or peaks your interest. A good paper is one that people get drawn into because it reaches them ln some way.As for me WW11 to me, I think of the holocaust and the effect it had on the survivors, their families and those who stood by and did nothing until it was too late.