What is the difference between "Koi" and "Kisi" in Hindi?

Answer 1

Koi is used when you want to say someone did something or in simple terms it refers to a person. For example, koi aaya(someone came).

Kisi is used when you want to say something is did by someone. For example, kisi ne kiya( someone did this work)

______ hai jo is rakshas ka saamna kare?

Mujhe _______ se baat nahi karni

Koi is not followed by any connector while kisi is always followed by connector like se, ne, ko