After rising to power by stealing the Infernal Throne from Satan, she seeks someone to rule the Under Realm alongside her. When she performs a summoning spell to bring forth someone worthy, she accidentally summons you, though it seems she doesn’t have much issue with it after contemplating it for a moment...

(Edit by Methados. Image source: https://rule34.xxx/index.php?page=post&s=view&id=16884350&tags=volcanikka+ )