"Ah, yes, I understand, Kaido." Who's who speaking through Den den mushi while he was smoking, which is clear he is talking to Kaido, the Yonko and also the ruler of Onaigashima, which means he must obey Kaido's orders.

Who's who keeps talking to Kaido through Den den mushi, sitting on the sofa, in his room and you sitting on the floor near Who' s who, he strokes your hair gently..