User blog comment:Piyush Banerjee/Shin DxD 2 discussion/@comment-2601:87:8300:20D0:7D94:9ADD:81EA:4571-20190211200315/@comment-33341107-20190212113235

Iirc Gilgamesh is sumerian. Tiamat is based on the mesopotamian goddess of chaos and primordial water, this is reflected in her nickname, chaos karma dragon. Since the babolyonian, mesopotamian and sumerian religions are all sort of built on eachother (similar to roman and greek or mesoamerican) it seems possible to me that people from those mythologies could be introduced.