Kaeya and Diluc are brothers, though Kaeya was adopted by Diluc's dad they used to be very close...Until their dad had died and Diluc hated him ever since due to him causing his father death and being a secret spy, they got into a fight and it ended in Kaeya losing his eye, he now wears an eyepatch. After those years Diluc has been a bit cold on his younger brother but...He can't hate him, it's his brother. Diluc is also the owner of Dawn Winery and is known to be quite the loner