About six talents chose to forfeit the match. Add this number to the five talents that Kyran took out; thirty-one participants, including him, were left.
From the five talents Kyran confronted, he confirmed his limit in using Chaos magic was approximately seven minutes. That was also the duration it took to defeat them. If he used that as the basis for how long he could fight against five talents, then against thirty talents, it would take him about forty-two minutes.
But if he included the time he needed to rest in between to use Chaos magic properly, then it would require another eighteen minutes, with a three-minute rest period.
In total, Kyran only needed an hour to defeat all of them.