User blog comment:B214/Question and Answers 3/@comment-4547267-20140618023446/@comment-73.178.133.185-20140618143049

@DxDlover What's a "super devil witch"? : P

Rias is the heiress of the House of Gremory, nothing will change that. As Jop says, Issei would merely be her husband.

@15sok He wouldn't be a "trophy husband" but more along the lines of a "Duchess Consort" (see Queen Consort in real life). "Trophy husband/wife" refers to someone marrying another for their looks/family/money or such.