My Lovely Daughters are Both Sages: I'm a Black Mage Whose Special Skill is Debuffing, and the Twin Daughters I Raised Become S-Ranked Great Sages!

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?!