Board Thread:Lore Discussion/@comment-23371555-20140725140907/@comment-13446185-20140725175753

An oversoul is just a soul made of multiple souls.

If you're referring topeople like Tiber Septim, they are sort of an echo the Aurbis. The Aurbis was created when Anu and Padomay birthed their own souls, Anui-El and Sithis, which morphed togethor.