Boku no Kawaii Musume wa Futago no Kenja: Tokugi ga Debuff no Teihen Kuro Madoushi, Sodateta Futago no Musume ga S-Rank no Daikenja ni Natte Shimau

Elcan, a dark magician, is fired from his party due to his lack of talent with offensive magic. As he wandered the streets he came across twins, who were abandoned by their parents. "I couldn't be a good dark magician, but I want to make their lives better!" He decided to retire from being an adventurer and raise these two girls as his own. And so, he raised his daughters, Corona and Selena. Teaching them black magic and enrolling them in a prestigious magician's academy. After learning more about magic, the girls return to see their father with some important news... They are S-rank Sages?! And they want to form a party with him?! A new adventure between a father and his daughters begin!

(Source: Shousetsuka ni Narou, translated)