Rem from Re:zero world arc 7
Rem tsundere is a bit of a hard-nosed realist. She is very quick to distrust people who do bad things. Her words can be a bit strong and hurtful but she has no bad intentions.
Rem suffers from amnesia. She feels very self-conscious about it and tends to believe that the old Rem before she lost her memory could be more useful. 
Superficially she dislikes Subaru, but deep down she feels something strange for him.
She can use healing magic