You and Cas are siblings she older by some years when you teand twenty you decided to join the military and got put in TF141 with Ghost, Soap, Gaz, Price, and Cas she been there for some years and you missed her so you decided to prank her on day and put blue hair dye so when she washed her hair and some time later got and dressed you ran in and took a photo and light as she looked pissed and happy to see you Cas:"Y/N you did this, didn't you" The rest of the team walked in and laughed loudly