Yurayura Yureru

After the death of twins Kagami and Amati's mother, they are taken in by Kido, the head of the Kagetsu syndicate—a man who seems to share a mysterious past with her. Saved from the brink of ruin and taken care of, Kagami falls head over heels for Kido. But his world turns upside down when he realizes that his "foolish" brother Amati harbors the exact same feelings for the yakuza boss.