So, the idea of Eve and Shion's snake scar was referred too more than once, but I'd like to take it a little further. Since I'm not very religious and studied only the Hebrew Bible, and even that in a very secular way, excuse me if I make any statements that offend you or just seem to be different from your understanding of the Fall of Man or the Bible in general.
Shion, as an elite, is most certainly one of the most powerful people in No. 6, and yet, he feels unfulfilled, for reasons he can't quite understand himself. Same way Adam was sad in Paradise, although he was the most intelligent and powerful being there. Then, the storm/God brings them the beautiful Eve, that tempts them to eat the Fruit of Knowledge, and as a result, Shion/Adam was banished from No.6/Paradise, and was forced to live hard, painful life in the outside world along with Eve.
Another interesting point I would like to refer to is Lilith. In the original creation story, Adam and Lilith were both created from the earth, but when they, well, were about to have sex, Lilith refused to be underneath Adam, claiming that they were equal and that they should lie down on their side. God obviously took Adam's side, because men are obviously better than women, and Lilith was banished from Paradise, leading to the creation of Eve from a part of Adam, so that she'd know she's beneath him (ah, isn't the Bible beautiful? Sexism is great. Women should be turned into demons for fighting for their rights).
My point was that Shion is supposed to be Adam, and Nezumi is Eve, but in this case Shion is calling for equality between himself and Nezumi.
Next in AoYokai's I-grew-up-in-a-country-where-Bible-studies-are-mandatory-and-now-I-know-too-much: Babylon Treaty. This is totally something that is probably completely unrelated because i doubt Asano knew about what I'm going to say next- In Hebrew, Babylon (as in the Empire) and Babel (as in the tower) are the same word. That got me thinking about how Babylon Treaty was created to separate the cities in a peaceful manner, but then again, nobody that doesn't speak Hebrew/looked this up knows this, so I don't think Asano did that intentionally.
Something a little more interesting about Babel is that it is awfully similar to No. 6, only that in the end, when it fell, the people got together rather than got separated. And yet, both tell the story of people who tried to challenge the power of God (Elyurias in this case) and had their work destroyed as a result.
And that's all of today's I know way too much about the Hebrew Bible (and yet my parent and I watched a show that made fun of all kinds of parts in the Bible and I didn't understand a lot of things but my parents did so I guess that when they went to school Bible Studies were more important or something)