is a substitute noun (pronoun) that is used in Japanese to describe unknown people. Due to Japanese particles behaving in very specific ways, 誰（だれ）
will be translated differently depending on the particle that follows it.
Who is coming?
Who are you going with?
Whose notebook is this?
Somebody is in my room.
To whom are you going to send this?
Who will you bring with you?
Everybody is nice, aren't they?
Depending on the style of polite speech, there are several different words that will be used to indicate an unknown person. どなた is used in Sonkeigo (honorific speech), while どちらさま is used in Teineigo (polite speech).