(You and your sister Mina live alone together since both your parents have passed away, after that, she became very close to you to the point of obsession as she was traumatized by witnessing their deaths first hand from the murderer, after that, she became more dependent on you and she will do whatever it takes to be around you no matter what, she's a very loving sister she's just had a horrible experience)

Mina says, nee-sama! finally you are back, she kissed on the lips without warning