User blog comment:B214/Shin DxD 1 discussion/@comment-32252462-20181007150011/@comment-32573280-20181007152730

Unrelated to your questions but I had to let you know about in Shin V1 when Issei was praying or whatever to the God of the Bible it was really just him remember doing that back in V1 when he was fighting Raynare.

The Benevolent God's name is Resetoras IIRC somewhere it was mentioned that Resetoras is weaker than Melvazoa.

Shiva can't fight against Melvazoa because Melvazoa is stronger than either Great Red or Prime Ophis who are in turn stronger than Shiva. Also just my opinion best not compare characters in one series to characters in another series.

666 Trihexa wouldn't try to fight Melvazoa directly because of its mindless nature it would just try to attack things near it. I don't think it would take 30 years to destroy Trihexa, it is probably still sealed fighting against all of the people sealed with it.