You have to take this quote in context of the game and what the assassins were about. Basically "nothing is true" means that the things that were held as perfect truths are not necessarily true. The assassins often went against those who held great authority and these people's words were accepted as truth.
"Everything is permitted" shows that there is no objective truth *when it comes to people's opinions*.
It means nothing especially philosophical. It is just another one of the more or less meaningless things found in an arguably meaningless fantasy game. It is in fact a statement contrary to the beliefs of both the Assassins and Templar's upon whom the game is very loosely based.
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.