Demon lord of Zero (Fanfic version)

What happens when the "zero" Louise Valleriè summons the "sorcerer of destruction" Demon Lord Diablo and his soon to be wives? (This is my first ever fanfiction and my first ever time writing so go easy on me. I'll try not to do OC and mainly follow the Canon of the familiar of zero, the events would take place after vol 12 of the novel of how not to summon a Demon Lord.) Also this was supposed to be fanfic but for some reason it won't let me change it to fanfic