This is the 3759th most frequent Japanese word.
だれ
"Who" (used to ask about a person).
The word 'だれ' is used here as an interrogative pronoun to ask about an unknown person or individual.
だれが来たのか知っていますか？
Do you know who came?
In this sentence, 'だれ' is combined with 'か' to mean 'someone,' indicating possession by an unspecified person.
それはだれかのバッグです。
That is someone's bag.
Here, 'だれ' combined with 'でも' creates the expression meaning 'anyone,' indicating inclusivity of all individuals.