Haramasete Valkyrie

The main character is a low-class male angel. But one day, he is expelled from heaven. He meets Eleanor, a valkyrie, and begins to serve under her. A while later, he hears a rumor that one can get power by learning a special magic. However, he isn't strong enough to learn it.... So he decides to make Eleanor his sex slave and uses her as his tool. To do that, he thinks of confining Sigurd, Eleanor's ex-boyfriend. He successfully catches and confines Sigurd and calls Eleanor, Iris, and Eunice, Eleanor's daughter, to his fastness....