Well really, if you get right to the core, the very essence of both are very similar. It's simply because the idea of good/pure vs. evil/corrupt in any story can be directed back to The Word of God. This doesn't mean that Bungie went directly to it for themes but simply followed their nature as story tellers and wanted to tell the story of good vs. evil. This urge to do so has been around since we learned how to tell stories and it will most likely never cease. We are obsessed with it. Do you know why? We understand that good is...well good and want good to succeed. Our cup is never full though, we tell the same thing over and over and over again and again and again. The only difference is the packaging. Star Wars, LotR, Attack on Titan, Batman. They all tell the same thing. Good must win. Now I understand, this is much broader than what you ask. I'm simply saying that if you really get down to it, the Word of God is the root of it. Anyways so back to your post. Here's another example: If you read the Books of Sorrow, it tells a story of a being who sought after dark power, soled her soul for it and denied her very self and in turn became Oryx. He then created the hive. This is a great example of something that is good turned into evil by corruption. Life is a good thing and Oryx's purpose is to wipe out all life in the entire universe.