Eshawhich Good Family and Students Marry First and Then Fall in Love?

* It is an atypical paro and contains the idea of ​​marriage first, love later. It refers to some of the original works and is not complete. It may be quite long and has already been serialized...? ＊There are elements of Black and White E x Xia mentioned, and there is a little bit of unrequited love in the beginning (Xia → E) Mission: Marriage first, love later, save the world