Every Emperor had a dedicated Messenger looking for outstanding talents during the competition. When they spotted a contestant with enough potential, even if that contestant lost the match, they might still earn the Emperor's favor and enticement, thereby increasing the Emperor's power.
Because Tang San was human, he hadn't attracted much attention in the previous matches, not until he defeated the Behemoth giant beast in the last round and displayed his dual bloodline, which completely changed the situation. Before he left the stage, the Peacock Demon King had already dispersed all the Messengers who had come to communicate, claiming Tang San was one of his own from Jiali City. This was why Tang San hadn't received any communication from the Messengers of the Emperors.