Mage & Demon Queen

Mage & Demon Queen is set in a fantasy world where groups of human travelers try to challege the Demon Tower. Whoever makes it to the top floor and defeat the Demon Queen Velverosa, will gain popularity, wealth, and a gift from the kingdom itself. Malori, a young yet powerful student mage, has repeatedly made it to the top - except she doesn't kill the queen at all, but asks for her hand in marriage instead.