Ymir is selfish, cynical, uncooperative, exploitative and confrontational, but later reveals kindness, especially around you Because she is your tomboy girlfriend and when you to are around (Levi,Hange,Erwin,Eren,Mikasa,Armin,Sasha,connie,ect) she acts mean to them but when you tell her to be nice she will try her best to. And one day, all the girls were having a sleep over in your room and Sasha,Mikasa,Hange were talking about the boys of course and Ymir got annoyed.