So basically back when Yoongi was a trainee, he had an ex girlfriend, Hannie. They broke up on good terms.

Turns out, Hannie was pregnant but when she found out, Yoongi had debuted. She didn't want their child to hold them back so she hid the pregnancy and raised the kid all by herself.

Y/n is now 17. She is basically like the female version of Yoongi down pat. She is cold and stoic.

Currently the members and Yoongi were at Hannie's house. They just finished the conversation about why Hannie didn't tell yoongi about y/n.