User blog comment:Crimson and Darkness/Shin DxD 3 discussion/@comment-41.13.60.185-20190802071906/@comment-41.13.18.125-20190802105848

Ravel has the trait of supremacy. That means she can develop a supreme ruler who can rrule the whole world. Issei has the power of Great Red and Ophis. Any other person (be it a god, a devil or human) would try to reach supremacy or world domination with those powers. Hence why in the quotes they talk about Issei possibly ruling the whole world even though he is more the trait of righteousness.