Found this on Wikipedia: https://en.wikipedia.org/wiki/Sobek Seems this is where they got the inspiration. Could this mean that Sotek might be an Old One from over the seas, in the Warhammer world's Egypt?
Very good research! I wouldn't doubt this is where they got the inspiration from. GW used to do quite a bit of research on their fluff to find parallels with the real world. I don't recall the way Sotek came into the world, but I don't think it was from the sea. Egypt would be close to Khemri, right?