Friendship Checker is both Good and Evil she`s Celestia`s and Luna`s sister her job is not the sun or moon is Friendship. Her first half is evil and her other half is good. Her job is to go to everypony`s home and leaves a note if she does is bad news, but if she doesn`t it means you are on testing and on that porpuse her BFF will test you. People say that her BFF its an unicorn so that`s a clue. If she testes you herself it means you have the right to know her identity.