An Archdemon's Dilemma: How to Love Your Elf Bride

Maou no Ore ga Dorei Elf o Yome ni Shita ndaga, Dou Medereba Ii?
魔王の俺が奴隷エルフを嫁にしたんだが、どう愛でればいい?

Source

An Archdemon’s Dilemma: How to Love Your Elf Bride
Maou no Ore ga Dorei Elf o Yome ni Shita ndaga, Dou Medereba Ii?· 魔王の俺が奴隷エルフを嫁にしたんだが、どう愛でればいい?
novel

Zagan is feared by the masses as an evil sorcerer. Both socially awkward and foulmouthed, he spends his days studying sorcery while beating down any trespassers within his domain. One day he’s invited to a dark auction, and what he finds there is an elven slave girl of peerless beauty, Nephy. Having fallen in love at first sight, Zagan uses up his entire fortune to purchase her, but being a poor conversationalist, he has no idea how to properly interact with her. Thus, the awkward cohabitation of a sorcerer who has no idea how to convey his love and his slave who yearns for her master but has no idea how to appeal to him begins. *Source: J-Novel Club, Vol. 1*

Spin-off

An Archdemon’s (Friend’s) Dilemma: How to Babysit a Crybaby Knight
Akuyuu no Ore ga Ponkotsu Kishi o Miterarenai ndaga, Dou Sewa o Yakya Ii?: Madome Gaiden· 悪友の俺がポンコツ騎士を見てられないんだが、どう世話を焼きゃいい? ~まどめ外伝~
manga

Archdemon Zagan hires his unsavory friend, the sorcerer known as Purgatory Barbatos, to guard Archangel Chastille Lillqvist from the shadows. Barbatos takes to watching over the girl—which really means watching her constantly screw things up, trust people she shouldn’t, and inevitably bawl her eyes out. But something about Chastille and her waterworks may just have a special effect on the sourpuss sorcerer… The tale of this odd couple begins after the seventh volume of An Archdemon’s Dilemma: How to Love Your Elf Bride! *Source: J-Novel Club, Vol. 1*