The brother who secretly eats corn at night

Kaeya has been spoiling us from the get-go. I thought the sinners in Kaeya's profile were the cursed people of Khaenri'ah but apparently they were 5 specific people, one of which was Dainsleif's older brother.

in the game kagurabachi: the bachi-ing we actually find out that kagurabachi had a secret sister this whole time