It wasn't seen but it was stated, around ch 33 to 35 am think, but it's something along these lines, it's described in a single bubble or two so you might've missed it when scrolling too fast
Just me or every blonde babes have the worst personalities excpet when they are one of the main characters lol, anyways the part when they both got startled was so cute
I KNEW ITTTTT, RIGHT FROM THE START THAT THIS TWO WONT BE AA NORMAL STEP SIBMING AISUDHFHFHFJFUD THEY LOOK SOOOO CUTEEEEEE BUT I WAS LIKE AT FIRST "NO GIRL, NO BOY YOU GUYS ARE SIBLINGSSSSS, STEP SIBLINGS THAT IS" IM SHIPPING THESE STEP SIBLINGS AND NO ONE CAN STOP MEEEEE
It wasnt him boizs