|part of speech:
||what person or persons.
Who are you?
||used as a relative pronoun in reference to a specified person or persons.
It is she who asked to see you.
||the person or persons that; any person or persons that.
Is it who I think it is?
||used as a relative pronoun to introduce extra information in connection with the person just specified.
Her mother, who teaches art up at the college, is a good friend of mine.
||what kind of person.
Who do you think I am?