Rossweisse/Relationships

Rossweisse is a part of Rias's Peerage and wasn't interested in Issei but in Volume 12 after he became the Hero of the Underworld she wants Issei to have a date with her. She could be a possible candidate for the Harem that Issei wants. She also said to Issei to set up many future dates with her on the calendar because she is interested in him.