Supernatural (book one )

Catherine was the youngest Winchester a result of a one night stand John had with a women while on a hunt her mom never wanted a child and she contacted John and when he came to her apartment when he came I'm he found a note on her saying she's his and to care for her and she didn't want her and after that she was never seen again John didn't know what to do with a baby nor the time to raise it so he left her with Dean and Sam and they cared for each other Dean was more of a dad to her than John was and when they got older and Sam left for college and dad left she stayed with Dean when the boys first met cat John came to the hotel and told the boys that they have a baby sister at that time Dean was around 14-15 and Sam was around 10-11 and they loved their baby sister even with different moms she look almost identical to Sam she has dark brown hair and brown eyes but unlike the boys light tan skin she was pale, they came up with the nickname cat for her and it stuck they never call her Catherine unless getting scolded at.