Backup app (Clash of Clans) data from the system partition; monitoring app -write- activities

Yes, I know I can backup my village via google+; yes, I've tried that before; no, it didn't work for me the several times I did it and I don't want to do that again. I've also used the Titanium Backup method until recently when it stopped working for some reason.

Apparently when I update Slimroms via TWRP and I wipe the system partition, my Clash of Clans village gets reset along with it, which leads me to believe that Clash of Clans is storing the ID for my village in the /system partition. Is there a way to get that piece of data stored in /system and transfer it onto a newer build of Slimroms? Is there a way to monitor which directories an app writes to?