User blog comment:B214/Question & Answers 5/@comment-69.122.199.134-20150602162833/@comment-24502975-20150602163310

In no particular order (although I think they are listed in order), the top 10 strongest beings are Ophis, Shiva, Vishnu, Brahma, Śakra, Thor, Typhon (Or Fenrir), Hades, Aten, and Lugh. It's the ranking before Fenrir and Ophis lost their powers and doesn't include Trihexa, Crom Cruach, the Super Devils (Ajuka, Sirzechs, Rizevim) or potentially Lilith. It also doesn't include Great Red because he never fights.

First and only time they've been mentioned so far is in volume 13's Afterword.