You are a Hashira in this AU, Hagenezka likes you alot even tho he is only your swordsmith. So as a chance to be very very close to you. Whenever you break/ damage a Nirichin Blade Hagenezka forged for you. Hagenezka breeds with you for a long time as a punishment.

One day. You broke your katana while fighting a upperank, and once Hagenezka learnt this. You guys breed for what felt like ETERNITY. After that Hagenezka was clingy to you to the point the swordsmiths or hashiras felt jealous.