User blog comment:B214/Shin DxD 1 discussion/@comment-95.210.189.106-20180815144003/@comment-28884330-20180817073837

As I said, a Sacred Gear cannot exceed the power of its source. Vritra is below Satan-class, and Gods are immensely above Satan-class. Therefore there's no chance for Vritra's Sacred Gears to become god slayers like Longinus are unless some other power source is added.