I just don't like the Slytherin=bad stereotype. Yes, most bad people came from Slytherin, but it doesn't mean they're all bad. That's why I'd like to see Safu as Slytherin rather than Nezumi. I just feel like Nezumi is only Slytherin on the surface, but not on the inside. Safu would be a great example for the opposite- doesn't fit the stereotype of Slytherin, but she's a Slytherin on the deeper level. In my opinion...
Thinking about it again (as I said, I skimmed through this whole thing) snake would fit Nezumi better. I still want to find something better though...
@Weisel Nezumi being bullied by some Slytherin students (I imagine he would have a similar background story to Volde-however-you-spell-it-in-English only completely mudblood) and Shion letting him into the Hufflepuff dorms to hide, which might be against the rules (i don't remember) and then they both get detention and that's how they meet? Also, it's the first time Shion is exposed to discrimination of mudbloods and yeah...