Upon his return in season 11, it was finally confirmed that he was God. His status as God and His vile nature were hinted towards Him in His first appearance when the Winchesters confront him as "Chuck", who had been writing the Supernatural book series that detailed everything that happened to the Winchesters by then.

The Entity\n\n The Cosmic Entity might be the most powerful Supernatural monster in history, but there is not enough known about it to rank it very high on this list. The Entity predated God, the Darkness, and Death. However, the full power of the Entity is unknown, as we still don't know what its specific powers are yet.