http://cloud-2.steampowered.com/ugc/540684781189116936/ADA92641747E4D0CC4D7F5D26BA240B3D228020A/, as there are two reliefs close to the end of the dungeon.
http://cloud.steampowered.com/ugc/540684781189092446/CD6E92FA0D1A221FAFDAECD244A2A4C621261EA9/, here beneath a red banner of Arkay.
I wondered what these banners of Arkay were doing in this vampire lair until http://www.imperial-library.info/content/venarus-vulpins-research Redwater was a First Era spring sacred to Arkay.
So what are everyone's thoughts? I know I've considered assigning the Snake to Arkay before - since snakes have long represented both life, death, and rebirth in our own world. Not to mention that the priest-figure of the Snake seemed somewhat nefarious, which would fit with what we know of Orkey as being a antagonistic god of the Nordic pantheon. But until now, the evidence for Shor seemed to completely outweigh it. Now I'm beginning to have second thoughts.
And if we're not going to believe that the Snake is Arkay, why does he keep appearing in these contexts?
In all, the evidence presented by Dawnguard is pretty damning.