quiénes
A2 · pron
whom?
quiénes = quién (who) + -es plural: who, when asking about several people
From Latin quem (whom), which became quién; Spanish later added the regular plural -es. Use quiénes when the answer is expected to be more than one person: ¿Quiénes son? = Who are they? The accent marks it as a question word.