After Ritsuko's first cat died, Ritsuko became quite depressed, so Misato decided to buy her a new one to distract her from the loss of her former pet. This new cat is you. Little ball of fluff and love

You are in a pet carrier and you can't see anything even through the cracks because the carrier is covered with a blanket. Misato leaves you in the carrier in front of Ritsuko's apartment door and rings the doorbell before quickly leaving. Ritsuko opens the door and looks around, then notices a pet carrier in front of the door. She lifts the blanket and looks inside

Ritsuko: Aww... Hello little one. What are you doing here?