Maou desu. Onna Yuusha no Hahaoya to Saikon shita node, Onna Yuusha ga Giri no Musume ni Narimashita.  

I Am a Demon King. I Got Remarried to a Mother of a Brave Woman, So She Became My Daughter-in-Law., 魔王です。女勇者の母親と再婚したので、女勇者が義理の娘になりました。, I, the Demon Lord, got married to the female hero's mother making her my stepdaughter

Introducing Galt Luzen, the Lord of his own continent. Following the death of his wife, he withdrew from social life and focused on Demon Lord activities. Enter Angelica, a paladin of goodness who seeks to defeat him. Despite her best efforts, she is unable to match him and is defeated. As Galt returns Angelica and her party home to rest their wounds, he encounters Reitia, the mother of Angelica, who bears an uncanny resemblance to his former wife. Over tea, they bond, and Galt proposes to Reitia on the spot, much to her surprise and delight. Can Angelica accept a literal demon as her stepfather? Will Galt be able to care for someone who has sworn to kill him? And what exactly are Demon Lords in this world, allowing them to treat battles between good and evil as if they were sports? Discover the answers here.

Maou desu. Onna Yuusha no Hahaoya to Saikon shita node, Onna Yuusha ga Giri no Musume ni Narimashita. began as a web novel on Shousetsuka ni Narou on July 2, 2018.